Abstract

This specification describes a JavaScript API for performing basic cryptographic operations in web applications, such as hashing, signature generation and verification, and encryption and decryption. Additionally, it describes an API for applications to generate and/or manage the keying material necessary to perform these operations. Uses for this API range from user or service authentication, document or code signing, and the confidentiality and integrity of communications.

Introduction

The Web Cryptography API defines a low-level interface to interacting with cryptographic key material that is managed or exposed by user agents. The API itself is agnostic of the underlying implementation of key storage, but provides a common set of interfaces that allow rich web applications to perform operations such as signature generation and verification, hashing and verification, encryption and decryption, without requiring access to the raw keying material.

Cryptographic transformations are exposed via the {{SubtleCrypto}} interface, which defines a set of methods for performing common cryptographic operations. In addition to operations such as signature generation and verification, hashing and verification, and encryption and decryption, the API provides interfaces for key generation, key derivation and key import and export.

Use Cases

Multi-factor Authentication

A web application may wish to extend or replace existing username/password based authentication schemes with authentication methods based on proving that the user has access to some secret keying material. Rather than using transport-layer authentication, such as TLS client certificates, the web application may prefer the richer user experience provided by authenticating within the application itself.

Using the Web Cryptography API, the application could locate suitable client keys, which may have been previously generated via the user agent or pre-provisioned out-of-band by the web application. It could then perform cryptographic operations such as decrypting an authentication challenge followed by signing an authentication response.

This exchange could be further strengthened by binding the authentication to the TLS session over which the client is authenticating, by deriving a key based on properties of the underlying transport.

If a user does not already have a key associated with their account, the web application could direct the user agent to either generate a new key or to re-use an existing key of the user's choice.

Protected Document Exchange

A web application may wish to limit the viewership of documents that contain sensitive or personal information, even when these documents have been securely received, such as over TLS.

Using the Web Cryptography API, the application could do so by encrypting the documents with a secret key, and then wrapping that key with the public keys associated with the authorized viewers. When a user agent navigates to such a web application, the application would send the encrypted form of the document. The user agent is then instructed to unwrap the encryption key, using the user's private key, and from there, decrypt and display the document.

Cloud Storage

A web application may wish to permit users to protect the confidentiality of data and documents stored with remote service providers prior to uploading.

Using the Web Cryptography API, the application may have a user select a private or secret key, optionally derive an encryption key from the selected key, encrypt the document, and then upload the encrypted data to the service provider using existing APIs.

This use case is similar to the Protected Document Exchange use case, with viewership of the document limited to the user themself.

Document Signing

A web application may wish to accept electronic signatures on documents, in lieu of requiring physical signatures.

Using the Web Cryptography API, the application may direct the user to select a key, which may have been pre-provisioned out-of-band, or generated specifically for the web application. Using this key, the application may perform a signing operation over some data, as proof that the user accepts the document.

Data Integrity Protection

A web application may wish to cache data locally, while ensuring that this data cannot be modified in an offline attack.

Using the Web Cryptography API, the application may use a public key contained within the application to verify the contents of the data cache. Previously, when data was added to the cache, it would have been signed by the server with the corresponding private key. By validating the signature when restoring data from the cache, the client ensures that the cached data has not been tampered with.

Secure Messaging

A web application may wish to employ message layer security using schemes such as off-the-record (OTR) messaging, even when these messages have been securely received, such as over TLS.

The Web Cryptography API enables OTR and similar message signing schemes, by allowing key agreement to be performed. The two parties can negotiate shared encryption keys and message authentication code (MAC) keys, to allow encryption and decryption of messages, and to prevent tampering.

JavaScript Object Signing and Encryption (JOSE)

A web application may wish to interact with the structures and message formats defined by the IETF JavaScript Object Signing and Encryption (JOSE) Working Group.

Using the Web Cryptography API, the application may read and import keys encoded in the JSON key format (JWK), validate messages that have been integrity protected using digital signatures or MACs (JWS), or decrypt messages that have been encrypted (JWE).

The following conformance classes are defined by this specification:

conforming user agent

A user agent is considered to be a [= conforming user agent =] if it satisfies all of the MUST-, REQUIRED- and SHALL-level criteria in this specification that apply to implementations. This specification uses both the terms "conforming user agent" and "user agent" to refer to this product class.

Conformance requirements phrased as algorithms or specific steps may be implemented in any manner, so long as the end result is equivalent. (In particular, the algorithms defined in this specification are intended to be easy to follow, and not intended to be performant.)

User agents that use ECMAScript to implement the APIs defined in this specification MUST implement them in a manner consistent with the ECMAScript Bindings defined in the Web IDL specification [[WebIDL]] as this specification uses that specification and terminology.

Unless otherwise stated, string comparisons are done in a [= case-sensitive =] manner. String literals in this specification written in monospace font like "`this`" do not include the enclosing quotes.

Extensibility

Vendor-specific proprietary extensions to this specification are strongly discouraged. Authors must not use such extensions, as doing so reduces interoperability and fragments the user base, allowing only users of specific user agents to access the content in question.

If vendor-specific extensions are needed, the members should be prefixed by vendor-specific strings to prevent clashes with future versions of this specification. Extensions must be defined so that the use of extensions neither contradicts nor causes the non-conformance of functionality defined in the specification.

When vendor-neutral extensions to this specification are needed, either this specification can be updated accordingly, or an extension specification can be written that overrides the requirements in this specification. When someone applying this specification to their activities decides that they will recognize the requirements of such an extension specification, it becomes an applicable specification for the purposes of conformance requirements in this specification. Applicable specifications defined by the W3C Web Cryptography Working Group are listed in the table below.

Specification Reference
Readers are advised to consult the errata to this specification for updates to the table above.

Scope

Level of abstraction

The specification attempts to focus on the common functionality and features between various platform-specific or standardized cryptographic APIs, and avoid features and functionality that are specific to one or two implementations. As such this API allows key generation, management, and exchange with a level of abstraction that avoids developers needing to care about the implementation of the underlying key storage. The API is focused specifically around CryptoKey objects, as an abstraction for the underlying raw cryptographic keying material. The intent behind this is to allow an API that is generic enough to allow conforming user agents to expose keys that are stored and managed directly by the user agent, that may be stored or managed using isolated storage APIs such as per-user key stores provided by some operating systems, or within key storage devices such as secure elements, while allowing rich web applications to manipulate the keys and without requiring the web application be aware of the nature of the underlying key storage.

Cryptographic algorithms

Because the underlying cryptographic implementations will vary between conforming user agents, and may be subject to local policy, including but not limited to concerns such as government or industry regulation, security best practices, intellectual property concerns, and constrained operational environments, this specification does not dictate a mandatory set of algorithms that MUST be implemented. Instead, it defines a common set of bindings that can be used in an algorithm-independent manner, a common framework for discovering if a user agent or key handle supports the underlying algorithm, and a set of conformance requirements for the behaviors of individual algorithms, if implemented.

Out of scope

This API, while allowing applications to generate, retrieve, and manipulate keying material, does not specifically address the provisioning of keys in particular types of key storage, such as secure elements or smart cards. This is due to such provisioning operations often being burdened with vendor-specific details that make defining a vendor-agnostic interface an unsuitably unbounded task. Additionally, this API does not deal with or address the discovery of cryptographic modules, as such concepts are dependent upon the underlying user agent and are not concepts that are portable between common operating systems, cryptographic libraries, and implementations.

Concepts

Underlying Cryptographic Implementation

This specification assumes, but does not require, that conforming user agents do not and will not be directly implementing cryptographic operations within the user agent itself. Historically, many user agents have deferred cryptographic operations, such as those used within TLS, to existing APIs that are available as part of the underlying operating system or to third-party modules that are managed independently of the user agent.

The {{CryptoKey}} object represents the bridge between the JavaScript execution environment and these underlying libraries, through the use of the internal slot named {{CryptoKey/[[handle]]}}. The handle represents an opaque type that is implementation specific, which may not be represented within a JavaScript type, nor is it ever exposed to script authors. In this way, the {{CryptoKey}} object is the conceptual equivalent to the JavaScript executing environment as the {{CryptoKey/[[handle]]}} is to the underlying cryptographic implementation.

These APIs are traditionally built around a notion of cryptographic providers, an abstraction for a specific implementation of a set of algorithms. The operating system or library may come with a default provider, and users are frequently allowed to add additional providers, reconfigure the set of enabled algorithms, or otherwise customize how cryptographic services are provided.

While it is assumed that most user agents will be interacting with a cryptographic provider that is implemented purely in software, it is not required by this specification. As a result, the capabilities of some implementations may be limited by the capabilities of the underlying hardware, and, depending on how the user has configured the underlying cryptographic library, this may be entirely opaque to the User Agent.

Key Storage

This specification does not explicitly provide any new storage mechanisms for {{CryptoKey}} objects. Instead, by defining serialization and deserialization steps for {{CryptoKey}} objects, any existing or future web storage mechanisms that support storing serializable objects can be used to store {{CryptoKey}} objects.

In practice, it is expected that most authors will make use of the Indexed Database API [[INDEXEDDB]], which allows associative storage of key/value pairs, where the key is some string identifier meaningful to the application, and the value is a {{CryptoKey}} object. This allows the storage and retrieval of key material, without ever exposing that key material to the application or the JavaScript environment. Additionally, this allows authors the full flexibility to store any additional metadata with the {{CryptoKey}} itself.

Security considerations

Security considerations for implementers

By not providing an explicit storage mechanism, this specification assumes that {{CryptoKey}} objects are scoped to the current execution environment and any storage mechanisms available to that environment (e.g. Indexed Database API). Application authors rely upon this for the security of their applications; two origins with the same {{CryptoKey}} object have full access to the underlying key, and as such, messages from these applications cannot be distinguished, and messages sent to these applications can be fully recovered. Implementors should ensure that no {{CryptoKey}} objects are shared between two origins unless the author has explicitly chosen to share (e.g., such as through the use of postMessage)

A number of algorithms specified within this specification perform computationally intensive work, such as the generation of significantly large prime numbers, or through repeated iterations of a particular operation. As such, hostile applications may attempt to misuse this API and attempt to cause significant amount of work to be performed by an implementation, denying access or services to other applications that are executing. Implementations should take steps to mitigate these risks, such as limiting the amount of operations an implementation performs concurrently, requiring user consent for operations that may be known to be disruptive for the executing environment, or defining device-specific limits on attributes such as key sizes or iteration counts.

Security considerations for authors

This specification includes descriptions for a variety of cryptographic operations, some of which have known weaknesses when used inappropriately. Application developers must take care and review appropriate and current cryptographic literature, to understand and mitigate such issues. In general, application developers are strongly discouraged from inventing new cryptographic protocols; as with all applications, users of this specification will be best served through the use of existing protocols, of which this specification provides the necessary building blocks to implement.

In order to use the APIs defined in this specification to provide any meaningful cryptographic assurances, authors must be familiar with existing threats to web applications, as well as the underlying security model employed. Conceptually, issues such as script injection are the equivalent to remote code execution in other operating environments, and allowing hostile script to be injected may allow for the exfiltration of keys or data. Script injection may come from other applications, for which the judicious use of Content Security Policy may mitigate, or it may come from hostile network intermediaries, for which the use of Transport Layer Security may mitigate.

This specification does not define any specific mechanisms for the storage of cryptographic keys. By default, unless specific effort is taken by the author to persist keys, such as through the use of the Indexed Database API, keys created with this API will only be valid for the duration of the current page (e.g. until a navigation event). Authors that wish to use the same key across different pages or multiple browsing sessions must employ existing web storage technologies. Authors should be aware of the security assumptions of these technologies, such as the same-origin security model; that is, any application that shares the same scheme, host, and port have access to the same storage partition, even if other information, such as the path, may differ. Authors may explicitly choose to relax this security through the use of inter-origin sharing, such as `postMessage`.

Authors should be aware that this specification places no normative requirements on implementations as to how the underlying cryptographic key material is stored. The only requirement is that key material is not exposed to script, except through the use of the {{SubtleCrypto/exportKey}} and {{SubtleCrypto/wrapKey}} operations. In particular, it does not guarantee that the underlying cryptographic key material will not be persisted to disk, possibly unencrypted, nor that it will be inaccessible to users or other applications running with the same privileges as the User Agent. Any application or user that has access to the device storage may be able to recover the key material, even through scripts may be prohibited.

This specification places no normative requirements on how implementations handle key material once all references to it go away. That is, conforming user agents are not required to zeroize key material, and it may still be accessible on device storage or device memory, even after all references to the {{CryptoKey}} have gone away.

Applications may share a {{CryptoKey}} object across security boundaries, such as origins, through the use of the structured clone algorithm and APIs such as `postMessage`. While access to the underlying cryptographic key material may be restricted, based upon the {{CryptoKey/extractable}} attribute, once a key is shared with a destination origin, the source origin can not later restrict or revoke access to the key. As such, authors must be careful to ensure they trust the destination origin to take the same mitigations against hostile script that the source origin employs. Further, in the event of script injection on the source origin, attackers may post the key to an origin under attacker control. Any time that the user agent visits the attacker's origin, the user agent may be directed to perform cryptographic operations using that key, such as the decryption of existing messages or the creation of new, fraudulent messages.

Authors should be aware that users may, at any time, choose to clear the storage associated with an origin, potentially destroying keys. Applications that are meant to provide long-term storage, such as on the server, should consider techniques such as key escrow to prevent such data from being inaccessible. Authors should not presume that keys will be available indefinitely.

Security considerations for users

Users of applications that employ the APIs defined in this specification should be aware that these applications will have full access to all messages exchanged, regardless of the cryptography employed. That is, for messages that are encrypted, applications that use these APIs will have full access to the decrypted message as well.

Privacy considerations

Fingerprinting
By exposing additional APIs that reflect capabilities of the underlying platform, this specification may allow malicious applications to determine or distinguish different user agents or devices.
Super-cookies
This specification does not provide any means for malicious applications to create identifiers that outlive existing web storage technologies. However, care must be taken when introducing future revisions to this API or additional cryptographic capabilities, such as those that are hardware backed (e.g.: smart cards or Trusted Platform Modules). Considering that such storage is designed to prevent any two users from having the same underlying key data, such APIs may represent a real risk of being used as a permanent identifier against the user's wishes.
Use of {{Crypto/randomUUID}} as user ID
{{Crypto/randomUUID}} is useful for generating user IDs, but does not directly give any ability to generate global identifiers.

Dependencies

This specification relies on underlying specifications.

DOM

A [= conforming user agent =] MUST support at least the subset of the functionality defined in DOM that this specification relies upon; in particular, it MUST support {{Promise}}s and {{DOMException}}. [[DOM]]

HTML

A [= conforming user agent =] MUST support at least the subset of the functionality defined in HTML that this specification relies upon; in particular, it MUST support the {{ArrayBufferView}} typedef and serializable objects. [[HTML]]

Web IDL

A [= conforming user agent =] MUST be a conforming implementation of the IDL fragments in this specification, as described in the Web IDL specification. [[WebIDL]]

Terminology

The terms {{ArrayBuffer}}, {{ArrayBufferView}}, and serializable objects, are defined by the HTML specification [[HTML]].

The terms {{DOMString}} and {{BufferSource}} are defined in [[WEBIDL]].

An octet string is an ordered sequence of zero or more integers, each in the range 0 to 255 inclusive.

An octet string containing a bit string |b| is the [= octet string =] obtained by first appending zero or more bits of value zero to |b| such that the length of the resulting bit string is minimal and an integer multiple of 8 and then considering each consecutive sequence of 8 bits in that string as a binary integer, most significant bit first.

When this specification says to convert a non-negative integer |i| to an octet string of length |n|, where |n| * 8 is greater than the logarithm to base 2 of |i|, the user agent must first calculate the binary representation of |i|, most significant bit first, prefix this with sufficient zero bits to form a bit string of length |n| * 8, and then return the [= octet string =] formed by considering each consecutive sequence of 8 bits in that bit string as a binary integer, most significant bit first.

Comparing two strings in a case-sensitive manner means comparing them exactly, code point for code point.

Comparing two strings in a ASCII case-insensitive manner means comparing them exactly, code point for code point, except that the codepoints in the range U+0041 .. U+005A (i.e. LATIN CAPITAL LETTER A to LATIN CAPITAL LETTER Z) and the corresponding codepoints in the range U+0061 .. U+007A (i.e. LATIN SMALL LETTER A to LATIN SMALL LETTER Z) are also considered to match.

When this specification says to terminate the algorithm, the user agent must terminate the algorithm after finishing the step it is on. The algorithm referred to is the set of specification-defined processing steps, rather than the underlying cryptographic algorithm that may be in the midst of processing.

When this specification says to parse an ASN.1 structure, the user agent must perform the following steps:

  1. Let |data| be a sequence of bytes to be parsed.

  2. Let |structure| be the ASN.1 structure to be parsed.

  3. Let |exactData| be an optional boolean value. If it is not supplied, let it be initialized to `true`.

  4. Parse |data| according to the Distinguished Encoding Rules of [[X690]], using |structure| as the ASN.1 structure to be decoded.

  5. If |exactData| was specified, and all of the bytes of |data| were not consumed during the parsing phase, then [= exception/throw =] a {{DataError}}.

  6. Return the parsed ASN.1 structure.

When this specification says to parse a subjectPublicKeyInfo, the user agent must [= parse an ASN.1 structure =], with |data| set to the sequence of bytes to be parsed, |structure| as the ASN.1 structure of subjectPublicKeyInfo, as specified in [[RFC5280]], and |exactData| set to `true`.

When this specification says to parse a PrivateKeyInfo, the user agent must [= parse an ASN.1 structure =] with |data| set to the sequence of bytes to be parsed, |structure| as the ASN.1 structure of PrivateKeyInfo, as specified in [[RFC5208]], and |exactData| set to `true`.

When this specification says to parse a JWK, the user agent must run the following steps:

  1. Let |data| be the sequence of bytes to be parsed.

  2. Let |json| be the Unicode string that results from interpreting |data| according to UTF-8.

  3. Convert |json| to UTF-16.

  4. Let |result| be the object literal that results from executing the `JSON.parse` internal function in the context of a new global object, with `text` argument set to a JavaScript String containing |json|.

  5. Let |key| be the result of converting |result| to the IDL dictionary type of {{JsonWebKey}}.

  6. If the {{JsonWebKey/kty}} field of |key| is not defined, then [= exception/throw =] a {{DataError}}.

  7. Return |key|.

When this specification states to supply the contents of an ArrayBuffer named |data| to an underlying cryptographic implementation, the User Agent shall supply a contiguous sequence of bytes that is equal to the result of [= get a copy of the buffer source | getting a copy of the bytes =] held |data|.

When this specification says to calculate the usage intersection of two sequences, |a| and |b| the result shall be a sequence containing each [= recognized key usage value =] that appears in both |a| and |b|, in the order listed in the list of [= recognized key usage value=]s, where a value is said to appear in a sequence if an element of the sequence exists that is a case-sensitive string match for that value.

When this specification says to calculate the normalized value of a usages list, |usages| the result shall be the [= usage intersection =] of |usages| and a sequence containing all [= recognized key usage value =]s.

When this specification refers to the cached ECMAScript object associated with an internal slot [[|slot|]] of |object|, the user agent must run the following steps:

  1. If the [[|slot|_cached]] internal slot of |object| is undefined:
    Set the [[|slot|_cached]] internal slot of |object| to the result of performing type conversion to an ECMAScript object as defined in [[WebIDL]] to the contents of the [[|slot|]] internal slot of |object|.
  2. Return the contents of the [[|slot|_cached]] internal slot of |object|.

Crypto interface

The Crypto interface represents an interface to general purpose cryptographic functionality including a cryptographically strong pseudo-random number generator seeded with truly random values. 

partial interface mixin WindowOrWorkerGlobalScope {
  [SameObject] readonly attribute Crypto crypto;
};

[Exposed=(Window,Worker)]
interface Crypto {
  [SecureContext] readonly attribute SubtleCrypto subtle;
  ArrayBufferView getRandomValues(ArrayBufferView array);
  [SecureContext] DOMString randomUUID();
};
Implementations should generate cryptographically strong random values using well-established cryptographic pseudo-random number generators seeded with high-quality entropy, such as from an operating-system entropy source (e.g., "/dev/urandom"). This specification provides no lower-bound on the information theoretic entropy present in cryptographically strong random values, but implementations should make a best effort to provide as much entropy as practicable.
This interface defines a synchronous method for obtaining cryptographically strong random values. While some devices and implementations may support truly random cryptographic number generators or provide interfaces that block when there is insufficient entropy, implementations are discouraged from using these sources when implementing getRandomValues, both for performance and to avoid depleting the system of entropy. Instead, these sources should be used to seed a cryptographic pseudo-random number generator that can then return suitable values efficiently.

Methods and Parameters

The getRandomValues method

The getRandomValues method generates cryptographically strong random values. It must act as follows:

  1. If |array| is not an {{Int8Array}}, {{Uint8Array}}, {{Uint8ClampedArray}}, {{Int16Array}}, {{Uint16Array}}, {{Int32Array}}, {{Uint32Array}}, {{BigInt64Array}}, or {{BigUint64Array}}, then [= exception/throw =] a {{TypeMismatchError}} and [= terminate the algorithm =].

  2. If the `byteLength` of |array| is greater than 65536, [= exception/throw =] a {{QuotaExceededError}} and [= terminate the algorithm =].

  3. Overwrite all elements of |array| with cryptographically strong random values of the appropriate type.

  4. Return |array|.

Do not generate keys using the `getRandomValues` method. Use the {{SubtleCrypto/generateKey}} method instead.

The randomUUID method

The randomUUID method generates a new version 4 UUID and returns its namespace specific string representation as described in section 3 of [[RFC4122]]. To generate a random UUID:

  1. Let |bytes| be a [= byte sequence =] of length 16.
  2. Fill |bytes| with cryptographically secure random bytes.
  3. Set the 4 most significant bits of |bytes|[6], which represent the UUID version, to `0100`.
  4. Set the 2 most significant bits of |bytes|[8], which represent the UUID variant, to `10`.

  5. Return the [= string/concatenate | string concatenation =] of «

    1. [= hexadecimal representation =] of |bytes|[0], [= hexadecimal representation =] of |bytes|[1], [= hexadecimal representation =] of |bytes|[2], [= hexadecimal representation =] of |bytes|[3],
    2. "`-`",
    3. [= hexadecimal representation =] of |bytes|[4], [= hexadecimal representation =] of |bytes|[5],
    4. "`-`",
    5. [= hexadecimal representation =] of |bytes|[6], [= hexadecimal representation =] of |bytes|[7],
    6. "`-`",
    7. [= hexadecimal representation =] of |bytes|[8], [= hexadecimal representation =] of |bytes|[9],
    8. "`-`",
    9. [= hexadecimal representation =] of |bytes|[10], [= hexadecimal representation =] of |bytes|[11], [= hexadecimal representation =] of |bytes|[12], [= hexadecimal representation =] of |bytes|[13], [= hexadecimal representation =] of |bytes|[14], [= hexadecimal representation =] of |bytes|[15]

    ».

For the steps described in the algorithm to [= generate a random UUID =], the hexadecimal representation of a byte |value| is the two-character string created by expressing |value| in hexadecimal using [= ASCII lower hex digits =], left-padded with "`0`" to reach two [= ASCII lower hex digits =].

Attributes

The subtle attribute

The subtle attribute provides an instance of the {{SubtleCrypto}} interface which provides low-level cryptographic primitives and algorithms.

Algorithm dictionary

The Algorithm object is a dictionary object [[WEBIDL]] which is used to specify an algorithm and any additional parameters required to fully specify the desired operation. 

typedef (object or DOMString) AlgorithmIdentifier;

typedef AlgorithmIdentifier HashAlgorithmIdentifier;

dictionary Algorithm {
  required DOMString name;
};

{{Algorithm}} Dictionary Members

name
The name of the registered algorithm to use.

KeyAlgorithm dictionary

The KeyAlgorithm dictionary represents information about the contents of a given {{CryptoKey}} object. 

dictionary KeyAlgorithm {
  required DOMString name;
};

Description

The {{KeyAlgorithm}} dictionary is provided to aid in documenting how fixed, public properties of a {{CryptoKey}} are reflected back to an application. The actual dictionary type is never exposed to applications.

KeyAlgorithm dictionary members

name
The name of the algorithm used to generate the {{CryptoKey}}

CryptoKey interface

The CryptoKey object represents an opaque reference to keying material that is managed by the user agent. 

enum KeyType { "public", "private", "secret" };

enum KeyUsage { "encrypt", "decrypt", "sign", "verify", "deriveKey", "deriveBits", "wrapKey", "unwrapKey" };

[SecureContext,Exposed=(Window,Worker),Serializable]
interface CryptoKey {
  readonly attribute KeyType type;
  readonly attribute boolean extractable;
  readonly attribute object algorithm;
  readonly attribute object usages;
};

Description

This specification provides a uniform interface for many different kinds of keying material managed by the user agent. This may include keys that have been generated by the user agent, derived from other keys by the user agent, imported to the user agent through user actions or using this API, pre-provisioned within software or hardware to which the user agent has access or made available to the user agent in other ways. The term key refers broadly to any keying material including actual keys for cryptographic operations and secret values obtained within key derivation or exchange operations.

The CryptoKey object is not required to directly interface with the underlying key storage mechanism, and may instead simply be a reference for the user agent to understand how to obtain the keying material when needed, e.g. when performing a cryptographic operation.

Key interface data types

KeyType
The type of a key. The recognized key type values are "`public`", "`private`" and "`secret`". Opaque keying material, including that used for symmetric algorithms, is represented by secret, while keys used as part of asymmetric algorithms composed of public/private keypairs will be either public or private.
KeyUsage
A type of operation that may be performed using a key. The recognized key usage values are encrypt, decrypt, sign, verify, deriveKey, deriveBits, wrapKey and unwrapKey.

CryptoKey internal slots

Every {{CryptoKey}} object has a set of internal slots that store information about the key. These slots are not exposed as part of this specification; they represent internal state that an implementation uses to implement this specification. The notational convention used in [[ECMA-262]] is re-used here; internal slots are identified by names enclosed in double square brackets [[ ]].

All {{CryptoKey}} objects have internal slots named [[\type]], [[\extractable]], [[\algorithm]], [[\algorithm_cached]], [[\usages]], [[\usages_cached]], and [[\handle]].

The contents of the {{CryptoKey/[[algorithm]]}} internal slot shall be, or be derived from, a {{KeyAlgorithm}}. The contents of the {{CryptoKey/[[usages]]}} internal slot shall be of type Sequence<KeyUsage>.

The {{CryptoKey/[[handle]]}} slot is an opaque type that contains whatever data the underlying cryptographic implementation uses to represent a logical key. Different cryptographic implementations may use different types, ranging from opaque identifiers represented as integers, pointer types, or structures that provide identifying information. These handles are never exposed to applications.

CryptoKey interface members

type
Reflects the {{CryptoKey/[[type]]}} internal slot, which contains the type of the underlying key.
extractable
Reflects the {{CryptoKey/[[extractable]]}} internal slot, which indicates whether or not the raw keying material may be exported by the application.
algorithm
Returns the [= cached ECMAScript object =] associated with the {{CryptoKey/[[algorithm]]}} internal slot.
usages
Returns the [= cached ECMAScript object =] associated with the {{CryptoKey/[[usages]]}} internal slot, which indicates which cryptographic operations are permissible to be used with this key.

Serialization and deserialization steps

{{CryptoKey}} objects are serializable objects. Their [= serialization steps =], given |value| and |serialized|, are:

  1. Set |serialized|.[[\Type]] to the {{CryptoKey/[[type]]}} internal slot of |value|.
  2. Set |serialized|.[[\Extractable]] to the {{CryptoKey/[[extractable]]}} internal slot of |value|.
  3. Set |serialized|.[[\Algorithm]] to the [= sub-serialization =] of the {{CryptoKey/[[algorithm]]}} internal slot of |value|.
  4. Set |serialized|.[[\Usages]] to the [= sub-serialization =] of the {{CryptoKey/[[usages]]}} internal slot of |value|.
  5. Set |serialized|.[[\Handle]] to the {{CryptoKey/[[handle]]}} internal slot of |value|.

Their [= deserialization steps =], given |serialized| and |value|, are:

  1. Initialize the {{CryptoKey/[[type]]}} internal slot of |value| to |serialized|.[[\Type]].
  2. Initialize the {{CryptoKey/[[extractable]]}} internal slot of |value| to |serialized|.[[\Extractable]].
  3. Initialize the {{CryptoKey/[[algorithm]]}} internal slot of |value| to the [= sub-deserialization =] of |serialized|.[[\Algorithm]].
  4. Initialize the {{CryptoKey/[[usages]]}} internal slot of |value| to the [= sub-deserialization =] of |serialized|.[[\Usages]].
  5. Initialize the {{CryptoKey/[[handle]]}} internal slot of |value| to |serialized|.[[\Handle]].
When deserializing a serialized {{CryptoKey}} object, it is important that the object is not deserialized as a different type. This is normatively required by the definition of the [= deserialization steps =], but it merits specific attention, as such deserialization may expose the contents of the key material, which in some cases (such as when the {{CryptoKey/[[extractable]]}} internal slot is false) should not be exposed to applications.

SubtleCrypto interface

The SubtleCrypto interface provides a set of methods for dealing with low-level cryptographic primitives and algorithms. 

enum KeyFormat { "raw", "spki", "pkcs8", "jwk" };

[SecureContext,Exposed=(Window,Worker)]
interface SubtleCrypto {
  Promise<any> encrypt(AlgorithmIdentifier algorithm,
                       CryptoKey key,
                       BufferSource data);
  Promise<any> decrypt(AlgorithmIdentifier algorithm,
                       CryptoKey key,
                       BufferSource data);
  Promise<any> sign(AlgorithmIdentifier algorithm,
                    CryptoKey key,
                    BufferSource data);
  Promise<any> verify(AlgorithmIdentifier algorithm,
                      CryptoKey key,
                      BufferSource signature,
                      BufferSource data);
  Promise<any> digest(AlgorithmIdentifier algorithm,
                      BufferSource data);

  Promise<any> generateKey(AlgorithmIdentifier algorithm,
                          boolean extractable,
                          sequence<KeyUsage> keyUsages );
  Promise<any> deriveKey(AlgorithmIdentifier algorithm,
                         CryptoKey baseKey,
                         AlgorithmIdentifier derivedKeyType,
                         boolean extractable,
                         sequence<KeyUsage> keyUsages );
  Promise<ArrayBuffer> deriveBits(AlgorithmIdentifier algorithm,
                          CryptoKey baseKey,
                          unsigned long length);

  Promise<CryptoKey> importKey(KeyFormat format,
                         (BufferSource or JsonWebKey) keyData,
                         AlgorithmIdentifier algorithm,
                         boolean extractable,
                         sequence<KeyUsage> keyUsages );
  Promise<any> exportKey(KeyFormat format, CryptoKey key);

  Promise<any> wrapKey(KeyFormat format,
                       CryptoKey key,
                       CryptoKey wrappingKey,
                       AlgorithmIdentifier wrapAlgorithm);
  Promise<CryptoKey> unwrapKey(KeyFormat format,
                         BufferSource wrappedKey,
                         CryptoKey unwrappingKey,
                         AlgorithmIdentifier unwrapAlgorithm,
                         AlgorithmIdentifier unwrappedKeyAlgorithm,
                         boolean extractable,
                         sequence<KeyUsage> keyUsages );
};

The {{SubtleCrypto}} interface is named "SubtleCrypto" to reflect the fact that many of these algorithms have subtle usage requirements in order to provide the required algorithmic security guarantees.

For example, the direct use of an unauthenticated encryption scheme, such as AES in counter mode, gives potential attackers the ability to manipulate bits in the output by manipulating bits in the input, compromising the integrity of the message. However, AES-CTR can be used securely in combination with other cryptographic primitives, such as message authentication codes, to ensure the integrity of the protected message, but only when the message authentication code is constructed over the encrypted message and IV.

Developers making use of the SubtleCrypto interface are expected to be aware of the security concerns associated with both the design and implementation of the various algorithms provided. The raw algorithms are provided in order to allow developers maximum flexibility in implementing a variety of protocols and applications, each of which may represent the composition and security parameters in a unique manner that necessitate the use of the raw algorithms.

Data Types

KeyFormat
Specifies a serialization format for a key. The recognized key format values are:
raw
An unformatted sequence of bytes. Intended for secret keys.
pkcs8
The DER encoding of the PrivateKeyInfo structure from [[RFC5208]].
spki
The DER encoding of the SubjectPublicKeyInfo structure from [[RFC5280]].
jwk
The key is a {{JsonWebKey}} dictionary encoded as a JavaScript object

Methods and Parameters

Unless otherwise stated, objects created by the methods defined in this section shall be associated with the [= relevant realm =] of [= this =].

All errors are reported asynchronously by rejecting the returned Promise. This includes Web IDL type mapping errors.

The encrypt method

The encrypt method returns a new Promise object that will encrypt data using the specified {{AlgorithmIdentifier}} with the supplied {{CryptoKey}}. It must act as follows:

  1. Let |algorithm| and |key| be the `algorithm` and `key` parameters passed to the {{SubtleCrypto/encrypt()}} method, respectively.

  2. Let |data| be the result of [= get a copy of the buffer source | getting a copy of the bytes =] held by the `data` parameter passed to the {{SubtleCrypto/encrypt()}} method.

  3. Let |normalizedAlgorithm| be the result of normalizing an algorithm, with `alg` set to |algorithm| and `op` set to "`encrypt`".

  4. If an error occurred, return a Promise rejected with |normalizedAlgorithm|.

  5. Let |promise| be a new Promise.

  6. Return |promise| and perform the remaining steps [= in parallel =].

  7. If the following steps or referenced procedures say to [= exception/throw =] an error, reject |promise| with the returned error and then [= terminate the algorithm =].

  8. If the {{Algorithm/name}} member of |normalizedAlgorithm| is not equal to the {{KeyAlgorithm/name}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| then [= exception/throw =] an {{InvalidAccessError}}.

  9. If the {{CryptoKey/[[usages]]}} internal slot of |key| does not contain an entry that is "`encrypt`", then [= exception/throw =] an {{InvalidAccessError}}.

  10. Let |ciphertext| be the result of performing the encrypt operation specified by |normalizedAlgorithm| using |algorithm| and |key| and with |data| as |plaintext|.

  11. Resolve |promise| with |ciphertext|.

The decrypt method

The decrypt method returns a new Promise object that will decrypt data using the specified {{AlgorithmIdentifier}} with the supplied {{CryptoKey}}. It must act as follows:

  1. Let |algorithm| and |key| be the `algorithm` and `key`parameters passed to the {{SubtleCrypto/decrypt()}} method, respectively.

  2. Let |data| be the result of [= get a copy of the buffer source | getting a copy of the bytes held by =] the `data` parameter passed to the {{SubtleCrypto/decrypt()}} method.

  3. Let |normalizedAlgorithm| be the result of normalizing an algorithm, with `alg` set to |algorithm| and `op` set to "`decrypt`".

  4. If an error occurred, return a Promise rejected with |normalizedAlgorithm|.

  5. Let |promise| be a new Promise.

  6. Return |promise| and the remaining steps [= in parallel =].

  7. If the following steps or referenced procedures say to [= exception/throw =] an error, reject |promise| with the returned error and then [= terminate the algorithm =].

  8. If the {{Algorithm/name}} member of |normalizedAlgorithm| is not equal to the {{KeyAlgorithm/name}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| then [= exception/throw =] an {{InvalidAccessError}}.

  9. If the {{CryptoKey/[[usages]]}} internal slot of |key| does not contain an entry that is "`decrypt`", then [= exception/throw =] an {{InvalidAccessError}}.

  10. Let |plaintext| be the result of performing the decrypt operation specified by |normalizedAlgorithm| using |key| and |algorithm| and with |data| as |ciphertext|.

  11. Resolve |promise| with |plaintext|.

The sign method

The sign method returns a new Promise object that will sign data using the specified {{AlgorithmIdentifier}} with the supplied {{CryptoKey}}. It must act as follows:

  1. Let |algorithm| and |key| be the `algorithm` and `key` parameters passed to the {{SubtleCrypto/sign()}} method, respectively.

  2. Let |data| be the result of [= get a copy of the buffer source | getting a copy of the bytes held by =] the `data` parameter passed to the {{SubtleCrypto/sign()}} method.

  3. Let |normalizedAlgorithm| be the result of normalizing an algorithm, with `alg` set to |algorithm| and `op` set to "`sign`".

  4. If an error occurred, return a Promise rejected with |normalizedAlgorithm|.

  5. Let |promise| be a new Promise.

  6. Return |promise| and perform the remaining steps [= in parallel =].

  7. If the following steps or referenced procedures say to [= exception/throw =] an error, reject |promise| with the returned error and then [= terminate the algorithm =].

  8. If the {{Algorithm/name}} member of |normalizedAlgorithm| is not equal to the {{KeyAlgorithm/name}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| then [= exception/throw =] an {{InvalidAccessError}}.

  9. If the {{CryptoKey/[[usages]]}} internal slot of |key| does not contain an entry that is "`sign`", then [= exception/throw =] an {{InvalidAccessError}}.

  10. Let |result| be the result of performing the sign operation specified by |normalizedAlgorithm| using |key| and |algorithm| and with |data| as |message|.

  11. Resolve |promise| with |result|.

The verify method

The verify method returns a new Promise object that will verify data using the specified {{AlgorithmIdentifier}} with the supplied {{CryptoKey}}. It must act as follows:

  1. Let |algorithm| and |key| be the `algorithm` and `key` parameters passed to the {{SubtleCrypto/verify()}} method, respectively.

  2. Let |signature| be the result of [= get a copy of the buffer source | getting a copy of the bytes held by =] the `signature` parameter passed to the {{SubtleCrypto/verify()}} method.

  3. Let |data| be the result of [= get a copy of the buffer source | getting a copy of the bytes held by =] the `data` parameter passed to the {{SubtleCrypto/verify()}} method.

  4. Let |normalizedAlgorithm| be the result of normalizing an algorithm, with `alg` set to |algorithm| and `op` set to "`verify`".

  5. If an error occurred, return a Promise rejected with |normalizedAlgorithm|.

  6. Let |promise| be a new Promise.

  7. Return |promise| and perform the remaining steps[= in parallel =].

  8. If the following steps or referenced procedures say to [= exception/throw =] an error, reject |promise| with the returned error and then [= terminate the algorithm =].

  9. If the {{Algorithm/name}} member of |normalizedAlgorithm| is not equal to the {{KeyAlgorithm/name}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| then [= exception/throw =] an {{InvalidAccessError}}.

  10. If the {{CryptoKey/[[usages]]}} internal slot of |key| does not contain an entry that is "`verify`", then [= exception/throw =] an {{InvalidAccessError}}.

  11. Let |result| be the result of performing the verify operation specified by |normalizedAlgorithm| using |key|, |algorithm| and |signature| and with |data| as |message|.

  12. Resolve |promise| with |result|.

The digest method

The digest method returns a new Promise object that will digest data using the specified {{AlgorithmIdentifier}}. It must act as follows:

  1. Let |algorithm| be the `algorithm` parameter passed to the {{SubtleCrypto/digest()}} method.

  2. Let |data| be the result of [= get a copy of the buffer source | getting a copy of the bytes held by =] the `data` parameter passed to the {{SubtleCrypto/digest()}} method.

  3. Let |normalizedAlgorithm| be the result of normalizing an algorithm, with `alg` set to |algorithm| and `op` set to "`digest`".

  4. If an error occurred, return a Promise rejected with |normalizedAlgorithm|.

  5. Let |promise| be a new Promise.

  6. Return |promise| and perform the remaining steps [= in parallel =].

  7. If the following steps or referenced procedures say to [= exception/throw =] an error, reject |promise| with the returned error and then [= terminate the algorithm =].

  8. Let |result| be the result of performing the digest operation specified by |normalizedAlgorithm| using |algorithm|, with |data| as |message|.

  9. Resolve |promise| with |result|.

The generateKey method

When invoked, generateKey MUST perform the following steps:

  1. Let |algorithm|, |extractable| and |usages| be the `algorithm`, `extractable` and `keyUsages` parameters passed to the {{SubtleCrypto/generateKey()}} method, respectively.

  2. Let |normalizedAlgorithm| be the result of normalizing an algorithm, with `alg` set to |algorithm| and `op` set to "`generateKey`".

  3. If an error occurred, return a Promise rejected with |normalizedAlgorithm|.

  4. Let |promise| be a new Promise.

  5. Return |promise| and perform the remaining steps [= in parallel =].

  6. If the following steps or referenced procedures say to [= exception/throw =] an error, reject |promise| with the returned error and then [= terminate the algorithm =].

  7. Let |result| be the result of performing the generate key operation specified by |normalizedAlgorithm| using |algorithm|, |extractable| and |usages|.

  8. If |result| is a {{CryptoKey}} object:

    If the {{CryptoKey/[[type]]}} internal slot of |result| is {{KeyType/"secret"}} or {{KeyType/"private"}} and |usages| is empty, then [= exception/throw =] a {{SyntaxError}}.

    If |result| is a {{CryptoKeyPair}} object:

    If the {{CryptoKey/[[usages]]}} internal slot of the {{CryptoKeyPair/privateKey}} attribute of |result| is the empty sequence, then [= exception/throw =] a {{SyntaxError}}.

  9. Resolve |promise| with |result|.

The deriveKey method

When invoked, deriveKey MUST perform the following steps:

  1. Let |algorithm|, |baseKey|, |derivedKeyType|, |extractable| and |usages| be the `algorithm`, `baseKey`, `derivedKeyType`, `extractable` and `keyUsages` parameters passed to the {{SubtleCrypto/deriveKey()}} method, respectively.

  2. Let |normalizedAlgorithm| be the result of normalizing an algorithm, with `alg` set to |algorithm| and `op` set to "`deriveBits`".

  3. If an error occurred, return a Promise rejected with |normalizedAlgorithm|.

  4. Let |normalizedDerivedKeyAlgorithmImport| be the result of normalizing an algorithm, with `alg` set to |derivedKeyType| and `op` set to "`importKey`".

  5. If an error occurred, return a Promise rejected with |normalizedDerivedKeyAlgorithmImport|.

  6. Let |normalizedDerivedKeyAlgorithmLength| be the result of normalizing an algorithm, with `alg` set to |derivedKeyType| and `op` set to "`get key length`".

  7. If an error occurred, return a Promise rejected with |normalizedDerivedKeyAlgorithmLength|.

  8. Let |promise| be a new Promise.

  9. Return |promise| and perform the remaining steps [= in parallel =].

  10. If the following steps or referenced procedures say to [= exception/throw =] an error, reject |promise| with the returned error and then [= terminate the algorithm =].

  11. If the {{Algorithm/name}} member of |normalizedAlgorithm| is not equal to the {{KeyAlgorithm/name}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |baseKey| then [= exception/throw =] an {{InvalidAccessError}}.

  12. If the {{CryptoKey/[[usages]]}} internal slot of |baseKey| does not contain an entry that is "`deriveKey`", then [= exception/throw =] an {{InvalidAccessError}}.

  13. Let |length| be the result of performing the get key length algorithm specified by |normalizedDerivedKeyAlgorithmLength| using |derivedKeyType|.

  14. Let |secret| be the result of performing the derive bits operation specified by |normalizedAlgorithm| using |key|, |algorithm| and |length|.

  15. Let |result| be the result of performing the import key operation specified by |normalizedDerivedKeyAlgorithmImport| using "`raw`" as |format|, |secret| as |keyData|, |derivedKeyType| as |algorithm| and using |extractable| and |usages|.

  16. If the {{CryptoKey/[[type]]}} internal slot of |result| is {{KeyType/"secret"}} or {{KeyType/"private"}} and |usages| is empty, then [= exception/throw =] a {{SyntaxError}}.

  17. Resolve |promise| with |result|.

The deriveBits method

When invoked, deriveBits MUST perform the following steps:

  1. Let |algorithm|, |baseKey| and |length|, be the `algorithm`, `baseKey` and `length` parameters passed to the {{SubtleCrypto/deriveBits()}} method, respectively.

  2. Let |normalizedAlgorithm| be the result of normalizing an algorithm, with `alg` set to |algorithm| and `op` set to "`deriveBits`".

  3. If an error occurred, return a Promise rejected with |normalizedAlgorithm|.

  4. Let |promise| be a new Promise object.

  5. Return |promise| and perform the remaining steps [= in parallel =].

  6. If the following steps or referenced procedures say to [= exception/throw =] an error, reject |promise| with the returned error and then [= terminate the algorithm =].

  7. If the {{Algorithm/name}} member of |normalizedAlgorithm| is not equal to the {{KeyAlgorithm/name}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |baseKey| then [= exception/throw =] an {{InvalidAccessError}}.

  8. If the {{CryptoKey/[[usages]]}} internal slot of |baseKey| does not contain an entry that is "`deriveBits`", then [= exception/throw =] an {{InvalidAccessError}}.

  9. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing the result of performing the derive bits operation specified by |normalizedAlgorithm| using |baseKey|, |algorithm| and |length|.

  10. Resolve |promise| with |result|.

The {{SubtleCrypto/importKey()}} method

When invoked, the importKey method MUST perform the following steps:

  1. Let |format|, |algorithm|, |extractable| and |usages|, be the `format`, `algorithm`, `extractable` and `keyUsages` parameters passed to the {{SubtleCrypto/importKey()}} method, respectively.

  2. If |format| is equal to the string {{KeyFormat/"raw"}}, {{KeyFormat/"pkcs8"}}, or {{KeyFormat/"spki"}}:

    1. If the `keyData` parameter passed to the {{SubtleCrypto/importKey()}} method is a {{JsonWebKey}} dictionary, [= exception/throw =] a {{TypeError}}.

    2. Let |keyData| be the result of [= get a copy of the buffer source | getting a copy of the bytes held by =] the `keyData` parameter passed to the {{SubtleCrypto/importKey()}} method.

    If |format| is equal to the string {{KeyFormat/"jwk"}}:

    1. If the `keyData` parameter passed to the {{SubtleCrypto/importKey()}} method is not a {{JsonWebKey}} dictionary, [= exception/throw =] a {{TypeError}}.

    2. Let |keyData| be the `keyData` parameter passed to the {{SubtleCrypto/importKey()}} method.

  3. Let |normalizedAlgorithm| be the result of normalizing an algorithm, with `alg` set to |algorithm| and `op` set to "`importKey`".

  4. If an error occurred, return a Promise rejected with |normalizedAlgorithm|.

  5. Let |promise| be a new Promise.

  6. Return |promise| and perform the remaining steps [= in parallel =].

  7. If the following steps or referenced procedures say to [= exception/throw =] an error, reject |promise| with the returned error and then [= terminate the algorithm =].

  8. Let |result| be the {{CryptoKey}} object that results from performing the import key operation specified by |normalizedAlgorithm| using |keyData|, |algorithm|, |format|, |extractable| and |usages|.

  9. If the {{CryptoKey/[[type]]}} internal slot of |result| is {{KeyType/"secret"}} or {{KeyType/"private"}} and |usages| is empty, then [= exception/throw =] a {{SyntaxError}}.

  10. Set the {{CryptoKey/[[extractable]]}} internal slot of |result| to |extractable|.

  11. Set the {{CryptoKey/[[usages]]}} internal slot of |result| to the [= normalized value =] of |usages|.

  12. Resolve |promise| with |result|.

Support of {{KeyFormat/"raw"}} key formats is encouraged for interoperability. Web developers should consult the test-suite for detailed information on implementations support of other key formats.

For structured key formats, {{KeyFormat/"spki"}}, {{KeyFormat/"pkcs8"}} and {{KeyFormat/"jwk"}}, fields that are not explicitly referred to in the key import procedures for an algorithm are ignored.

The {{SubtleCrypto/exportKey()}} method

When invoked, the exportKey method MUST perform the following steps:

  1. Let |format| and |key| be the `format` and `key` parameters passed to the {{SubtleCrypto/exportKey()}} method, respectively.

  2. Let |promise| be a new Promise.

  3. Return |promise| and perform the remaining steps [= in parallel =].

  4. If the following steps or referenced procedures say to [= exception/throw =] an error, reject |promise| with the returned error and then [= terminate the algorithm =].

  5. If the {{Algorithm/name}} member of the {{CryptoKey/[[algorithm]]}} internal slot of |key| does not identify a registered algorithm that supports the export key operation, then [= exception/throw =] a {{NotSupportedError}}.

  6. If the {{CryptoKey/[[extractable]]}} internal slot of |key| is false, then [= exception/throw =] an {{InvalidAccessError}}.

  7. Let |result| be the result of performing the export key operation specified by the {{CryptoKey/[[algorithm]]}} internal slot of |key| using |key| and |format|.

  8. Resolve |promise| with |result|.

Support of {{KeyFormat/"raw"}} key formats is encouraged for interoperability. Web developers should consult the test-suite for detailed information on implementations support of other key formats.

The wrapKey method

When invoked, the wrapKey method MUST perform the following steps:

  1. Let |format|, |key|, |wrappingKey| and |algorithm| be the `format`, `key`, `wrappingKey` and `wrapAlgorithm` parameters passed to the {{SubtleCrypto/wrapKey()}} method, respectively.

  2. Let |normalizedAlgorithm| be the result of normalizing an algorithm, with `alg` set to |algorithm| and `op` set to "`wrapKey`".

  3. If an error occurred, let |normalizedAlgorithm| be the result of normalizing an algorithm, with `alg` set to |algorithm| and `op` set to "`encrypt`".

  4. If an error occurred, return a Promise rejected with |normalizedAlgorithm|.

  5. Let |promise| be a new Promise.

  6. Return |promise| and perform the remaining steps [= in parallel =].

  7. If the following steps or referenced procedures say to [= exception/throw =] an error, reject |promise| with the returned error and then [= terminate the algorithm =].

  8. If the {{Algorithm/name}} member of |normalizedAlgorithm| is not equal to the {{KeyAlgorithm/name}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |wrappingKey| then [= exception/throw =] an {{InvalidAccessError}}.

  9. If the {{CryptoKey/[[usages]]}} internal slot of |wrappingKey| does not contain an entry that is "`wrapKey`", then [= exception/throw =] an {{InvalidAccessError}}.

  10. If the algorithm identified by the {{CryptoKey/[[algorithm]]}} internal slot of |key| does not support the export key operation, then [= exception/throw =] a {{NotSupportedError}}.

  11. If the {{CryptoKey/[[extractable]]}} internal slot of |key| is false, then [= exception/throw =] an {{InvalidAccessError}}.

    Because the wrapKey method effectively exports the key, only keys marked as extractable may be wrapped. In particular, this means that this API cannot create a wrapped JWK key that is marked as non-extractable using the {{JsonWebKey/ext}} JWK member.

    However, the unwrapKey method does support the JsonWebKey/ext}} JWK member, so that wrapped non-extractable keys created elsewhere, for example by a server, can be unwrapped using this API.

  12. Let |key| be the result of performing the export key operation specified the {{CryptoKey/[[algorithm]]}} internal slot of |key| using |key| and |format|.

  13. If |format| is equal to the strings {{KeyFormat/"raw"}}, {{KeyFormat/"pkcs8"}}, or {{KeyFormat/"spki"}}:
    Set |bytes| be set to |key|.
    If |format| is equal to the string {{KeyFormat/"jwk"}}:

    1. Convert |key| to an ECMAScript Object, as specified in [[WEBIDL]], performing the conversion in the context of a new global object.

    2. Let |json| be the result of representing |key| as a UTF-16 string conforming to the JSON grammar; for example, by executing the `JSON.stringify` algorithm specified in [[ECMA-262]] in the context of a new global object.

    3. Let |bytes| be the result of [= UTF-8 encode | UTF-8 encoding =] |json|.

    The key wrapping operations for some algorithms place constraints on the payload size. For example AES-KW requires the payload to be a multiple of 8 bytes in length and RSA-OAEP places a restriction on the length. For key formats that offer flexibility in serialization of a given key (for example JWK), implementations may choose to adapt the serialization to the constraints of the wrapping algorithm. This is why JSON.stringify is not normatively required, as otherwise it would prohibit implementations from introducing added padding.

  14. If |normalizedAlgorithm| supports the wrap key operation:

    Let |result| be the result of performing the wrap key operation specified by |normalizedAlgorithm| using |algorithm|, |wrappingKey| as |key| and |bytes| as |plaintext|.

    Otherwise, if |normalizedAlgorithm| supports the encrypt operation:

    Let |result| be the result of performing the encrypt operation specified by |normalizedAlgorithm| using |algorithm|, |wrappingKey| as |key| and |bytes| as |plaintext|.

    Otherwise:
    [= exception/throw =] a {{NotSupportedError}}.

  15. Resolve |promise| with |result|.

Support of {{KeyFormat/"raw"}} key formats is encouraged for interoperability. Web developers should consult the test-suite for detailed information on implementations support of other key formats.

The unwrapKey method

When invoked, the unwrapKey method MUST perform the following steps:

  1. Let |format|, |unwrappingKey|, |algorithm|, |unwrappedKeyAlgorithm|, |extractable| and |usages|, be the `format`, `unwrappingKey`, `unwrapAlgorithm`, `unwrappedKeyAlgorithm`, `extractable` and `keyUsages` parameters passed to the {{SubtleCrypto/unwrapKey()}} method, respectively.

  2. Let |wrappedKey| be the result of [= get a copy of the buffer source | getting a copy of the bytes held by =] the `wrappedKey` parameter passed to the {{SubtleCrypto/unwrapKey()}} method.

  3. Let |normalizedAlgorithm| be the result of normalizing an algorithm, with `alg` set to |algorithm| and `op` set to "`unwrapKey`".

  4. If an error occurred, let |normalizedAlgorithm| be the result of normalizing an algorithm, with `alg` set to |algorithm| and `op` set to "`decrypt`".

  5. If an error occurred, return a Promise rejected with |normalizedAlgorithm|.

  6. Let |normalizedKeyAlgorithm| be the result of normalizing an algorithm, with `alg` set to |unwrappedKeyAlgorithm| and `op` set to "`importKey`".

  7. If an error occurred, return a Promise rejected with |normalizedKeyAlgorithm|.

  8. Let |promise| be a new Promise.

  9. Return |promise| and perform the remaining steps [= in parallel =].

  10. If the following steps or referenced procedures say to [= exception/throw =] an error, reject |promise| with the returned error and then [= terminate the algorithm =].

  11. If the {{Algorithm/name}} member of |normalizedAlgorithm| is not equal to the {{KeyAlgorithm/name}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |unwrappingKey| then [= exception/throw =] an {{InvalidAccessError}}.

  12. If the {{CryptoKey/[[usages]]}} internal slot of |unwrappingKey| does not contain an entry that is "`unwrapKey`", then [= exception/throw =] an {{InvalidAccessError}}.

  13. If |normalizedAlgorithm| supports an unwrap key operation:
    Let |key| be the result of performing the unwrap key operation specified by |normalizedAlgorithm| using |algorithm|, |unwrappingKey| as |key| and |wrappedKey| as |ciphertext|.
    Otherwise, if |normalizedAlgorithm| supports a decrypt operation:
    Let |key| be the result of performing the decrypt operation specified by |normalizedAlgorithm| using |algorithm|, |unwrappingKey| as |key| and |wrappedKey| as |ciphertext|.
    Otherwise:
    [= exception/throw =] a {{NotSupportedError}}.
  14. If |format| is equal to the strings {{KeyFormat/"raw"}}, {{KeyFormat/"pkcs8"}}, or {{KeyFormat/"spki"}}:
    Set |bytes| be set to |key|.
    If |format| is equal to the string {{KeyFormat/"jwk"}}:
    Let |bytes| be the result of executing the [= parse a JWK =] algorithm, with |key| as the `data` to be parsed.

  15. Let |result| be the result of performing the import key operation specified by |normalizedKeyAlgorithm| using |unwrappedKeyAlgorithm| as |algorithm|, |format|, |usages| and |extractable| and with |bytes| as |keyData|.

  16. If the {{CryptoKey/[[type]]}} internal slot of |result| is {{KeyType/"secret"}} or {{KeyType/"private"}} and |usages| is empty, then [= exception/throw =] a {{SyntaxError}}.

  17. Set the {{CryptoKey/[[extractable]]}} internal slot of |result| to |extractable|.

  18. Set the {{CryptoKey/[[usages]]}} internal slot of |result| to the [= normalized value =] of |usages|.

  19. Resolve |promise| with |result|.

Support of {{KeyFormat/"raw"}} key formats is encouraged for interoperability. Web developers should consult the test-suite for detailed information on implementations support of other key formats.

Exceptions

The methods of the {{SubtleCrypto}} interface return errors by rejecting the returned promise with a predefined exception defined in ECMAScript [[ECMA-262]] or {{DOMException}}. The following predefined exceptions are used: {{TypeError}}. The following DOMException types from [[DOM]] are used:

Name Description
{{NotSupportedError}} The algorithm is not supported
{{SyntaxError}} A required parameter was missing or out-of-range
{{InvalidAccessError}} The requested operation is not valid for the provided key
{{DataError}} Data provided to an operation does not meet requirements
{{OperationError}} The operation failed for an operation-specific reason

When this specification says to [= exception/throw =] an error, the user agent must throw an error as described in [[WebIDL]]. When this occurs in a sub-algorithm, this results in termination of execution of the sub-algorithm and all ancestor algorithms until one is reached that explicitly describes procedures for catching exceptions. The error object thrown shall be associated with the [= relevant realm =] of [= this =].

JsonWebKey dictionary

dictionary RsaOtherPrimesInfo {
  // The following fields are defined in Section 6.3.2.7 of JSON Web Algorithms
  DOMString r;
  DOMString d;
  DOMString t;
};

dictionary JsonWebKey {
  // The following fields are defined in Section 3.1 of JSON Web Key
  DOMString kty;
  DOMString use;
  sequence<DOMString> key_ops;
  DOMString alg;

  // The following fields are defined in JSON Web Key Parameters Registration
  boolean ext;

  // The following fields are defined in Section 6 of JSON Web Algorithms
  DOMString crv;
  DOMString x;
  DOMString y;
  DOMString d;
  DOMString n;
  DOMString e;
  DOMString p;
  DOMString q;
  DOMString dp;
  DOMString dq;
  DOMString qi;
  sequence<RsaOtherPrimesInfo> oth;
  DOMString k;
};

The JsonWebKey dictionary provides a way to represent and exchange cryptographic keys represented by the JSON Web Key [[JWK]] structure, while allowing native and efficient use within Web Cryptography API applications.

The members of the RsaOtherPrimesInfo are defined in Section 6.3.2.7 of JSON Web Algorithms.

BigInteger

typedef Uint8Array BigInteger;

The BigInteger typedef is a {{Uint8Array}} that holds an arbitrary magnitude unsigned integer in big-endian order. Values read from the API SHALL have minimal typed array length (that is, at most 7 leading zero bits, except the value 0 which shall have length 8 bits). The API SHALL accept values with any number of leading zero bits, including the empty array, which represents zero.

Since the integer is unsigned, the highest order bit is NOT a sign bit. Implementors should take care when mapping to big integer implementations that expected signed integers.

CryptoKeyPair dictionary

dictionary CryptoKeyPair {
  CryptoKey publicKey;
  CryptoKey privateKey;
};

The CryptoKeyPair dictionary represents an asymmetric key pair that is comprised of both public (publicKey) and private (privateKey) keys.

Algorithms

Overview

In addition to providing a common interface to perform cryptographic operations, by way of the {{SubtleCrypto}} interface, this specification also provides descriptions for a variety of algorithms that authors may wish to use and that User Agents may choose to implement. This includes a selection of commonly-deployed symmetric and asymmetric algorithms, key derivation mechanisms, and methods for wrapping and unwrapping keys. Further, this specification defines a process to allow additional specifications to introduce additional cryptographic algorithms.

Concepts

Naming

Every cryptographic algorithm defined for use with the Web Cryptography API MUST have a unique name, referred to as its recognized algorithm name, such that no other specification defines the same case-insensitive string for use with the Web Cryptography API.

Supported Operations

Every cryptographic algorithm defined for use with the Web Cryptography API has a list of supported operations, which are a set of sub-algorithms to be invoked by the {{SubtleCrypto}} interface in order to perform the desired cryptographic operation. This specification makes use of the following operations:

  • encrypt
  • decrypt
  • sign
  • verify
  • digest
  • deriveBits
  • wrapKey
  • unwrapKey
  • generateKey
  • importKey
  • exportKey
  • get key length

If a given algorithm specification does not list a particular operation as supported, or explicitly lists an operation as not-supported, then the User Agent MUST behave as if the invocation of the sub-algorithm threw a NotSupportedError.

Normalization

Every cryptographic algorithm defined for use with the Web Cryptography API MUST define, for every [= supported operation =], the IDL type to use for [= algorithm normalization =], as well as the IDL type or types of the return values of the sub-algorithms.

Specification Conventions

Every cryptographic algorithm definition within this specification employs the following specification conventions. A section, titled "Registration", will include the [= recognized algorithm name =]. Additionally, it includes a table, which will list each of the supported operations as rows, identified by the Operation column. The contents of the Parameters column for a given row will contain the IDL type to use for [= algorithm normalization =] for that operation, and the contents of the Result column for that row indicate the IDL type that results from performing the supported operation.

If a conforming User Agent implements an algorithm, it MUST implement all of the supported operations and MUST return the IDL type specified.

Additionally, upon initialization, conforming User Agents must perform the [= define an algorithm =] steps for each of the supported operations, registering their IDL parameter type as indicated.

Unless otherwise stated, objects created by the operations defined in this specification shall be associated with the [= relevant realm =] of [= this =].

Algorithm Normalization

Description

The {{AlgorithmIdentifier}} typedef permits algorithms to either be specified as a {{DOMString}} or an object. The usage of {{DOMString}} is to permit authors a short-hand for noting algorithms that have no parameters (e.g. SHA-1). The usage of object is to allow an {{Algorithm}} (or appropriate subclass) to be specified, which contains all of the associated parameters for an object.

Because of this, it's necessary to define the algorithm for converting an {{AlgorithmIdentifier}} into an appropriate dictionary that is usable with this API. This algorithm must be extensible, so as to allow new cryptographic algorithms to be added, and consistent, so that Web IDL type mapping can occur before any control is returned to the calling script, which would potentially allow the mutation of parameters or the script environment.

Internal State Objects

This specification makes use of an internal object, supportedAlgorithms. This internal object is not exposed to applications.

Because this value is not exposed to applications, the exact type is not specified. It is only required to behave as an associative container of key/value pairs, where comparisons of keys are performed in a case-sensitive manner.

The initial contents of this internal object are as follows:

  1. For each value, |v| in the List of supported operations, set the |v| key of the internal object {{supportedAlgorithms}} to a new associative container.

Defining an Algorithm

The define an algorithm algorithm is used by specification authors to indicate how a user agent should normalize arguments for a particular algorithm. Its input is an algorithm name |alg|, represented as a DOMString, operation name |op|, represented as a DOMString, and desired IDL dictionary type |type|. The algorithm behaves as follows:

  1. Let |registeredAlgorithms| be the associative container stored at the |op| key of {{supportedAlgorithms}}.
  2. Set the |alg| key of |registeredAlgorithms| to the IDL dictionary type |type|.

Normalizing an algorithm

The normalize an algorithm algorithm defines a process for coercing inputs to a targeted IDL dictionary type, after Web IDL conversion has occurred. It is designed to be extensible, to allow future specifications to define additional algorithms, as well as safe for use with Promises. Its input is an operation name |op| and an {{AlgorithmIdentifier}} |alg|. Its output is either an IDL dictionary type or an error. It behaves as follows:

If |alg| is an instance of a DOMString:

Return the result of running the normalize an algorithm algorithm, with the `alg` set to a new {{Algorithm}} dictionary whose {{KeyAlgorithm/name}} attribute is |alg|, and with the `op` set to |op|.

If |alg| is an object:
  1. Let |registeredAlgorithms| be the associative container stored at the `op` key of {{supportedAlgorithms}}.
  2. Let |initialAlg| be the result of converting the ECMAScript object represented by |alg| to the IDL dictionary type {{Algorithm}}, as defined by [[WebIDL]].
  3. If an error occurred, return the error and terminate this algorithm.
  4. Let |algName| be the value of the {{Algorithm/name}} attribute of |initialAlg|.
  5. If |registeredAlgorithms| contains a key that is a [= case-insensitive =] string match for |algName|:

    1. Set |algName| to the value of the matching key.

    2. Let |desiredType| be the IDL dictionary type stored at |algName| in |registeredAlgorithms|.

    Otherwise:
    Return a new `NotSupportedError` and terminate this algorithm.
  6. Let |normalizedAlgorithm| be the result of converting the ECMAScript object represented by |alg| to the IDL dictionary type |desiredType|, as defined by [[WebIDL]].
  7. Set the {{Algorithm/name}} attribute of |normalizedAlgorithm| to |algName|.
  8. If an error occurred, return the error and terminate this algorithm.
  9. Let |dictionaries| be a list consisting of the IDL dictionary type |desiredType| and all of |desiredType|'s inherited dictionaries, in order from least to most derived.

  10. For each dictionary |dictionary| in |dictionaries|:

    1. For each dictionary member |member| declared on |dictionary|, in order:

      1. Let |key| be the identifier of |member|.
      2. Let |idlValue| be the value of the dictionary member with key name of |key| on |normalizedAlgorithm|.
      3. If |member| is of the type {{BufferSource}} and is present:
        Set the dictionary member on |normalizedAlgorithm| with key name |key| to the result of [= get a copy of the buffer source | getting a copy of the bytes held by =] |idlValue|, replacing the current value.
        If |member| is of the type {{HashAlgorithmIdentifier}}:
        Set the dictionary member on |normalizedAlgorithm| with key name |key| to the result of normalizing an algorithm, with the `alg` set to |idlValue| and the `op` set to "`digest`".
        If |member| is of the type {{AlgorithmIdentifier}}:
        Set the dictionary member on |normalizedAlgorithm| with key name |key| to the result of normalizing an algorithm, with the `alg` set to |idlValue| and the `op` set to the operation defined by the specification that defines the algorithm identified by |algName|.
      4. If an error occurred, return the error and terminate this algorithm.
  11. Return |normalizedAlgorithm|.

Recommendations

For Authors

As this API is meant to be extensible, in order to keep up with future developments within cryptography, there are no algorithms that conforming user agents are required to implement. As such, authors should check to see what algorithms are currently recommended and supported by implementations.

As highlighted in the Security Considerations, even cryptographic algorithms that might be considered strong for one purpose may be insufficient when used with another purpose. Authors should therefore proceed with extreme caution before inventing new cryptographic protocols.

Additionally, this specification includes several algorithms which, in their default usage, can result in cryptographic vulnerabilities. While these concerns may be mitigated, such as through the combination and composition with additional algorithms provided by this specification, authors should proceed with caution and review the relevant cryptographic literature before using a given algorithm. The inclusion of algorithms within this specification is not an indicator of their suitability for any or all purpose, and instead merely serve to provide as a specification for how a conforming User Agent must implement the given algorithm, if it choses to implement the algorithm.

For Implementers

In order to promote interoperability for developers, this specification includes a list of suggested algorithms. These are considered to be the most widely used algorithms in practice at the time of writing, and therefore provide a good starting point for initial implementations of this specification. The suggested algorithms are:

Algorithm Overview

The table below contains an overview of the algorithms described within this specification, as well as the set of SubtleCrypto methods the algorithm may be used with. In order for an algorithm to be used with a method the corresponding operation or operations, as defined in the procedures for the method, must be defined in the algorithm specification. Note that this mapping of methods to underlying operations is not one-to-one:

Application developers and script authors should not interpret this table as a recommendation for the use of particular algorithms. Instead, it simply documents what methods are supported. Authors should refer to the Security considerations for authors section of this document to better understand the risks and concerns that may arise when using certain algorithms.

Algorithm name encrypt decrypt sign verify digest generateKey deriveKey deriveBits importKey exportKey wrapKey unwrapKey
RSASSA-PKCS1-v1_5 ✔ ✔ ✔ ✔ ✔
RSA-PSS ✔ ✔ ✔ ✔ ✔
RSA-OAEP ✔ ✔ ✔ ✔ ✔ ✔ ✔
ECDSA ✔ ✔ ✔ ✔ ✔
ECDH ✔ ✔ ✔ ✔ ✔
AES-CTR ✔ ✔ ✔ ✔ ✔ ✔ ✔
AES-CBC ✔ ✔ ✔ ✔ ✔ ✔ ✔
AES-GCM ✔ ✔ ✔ ✔ ✔ ✔ ✔
AES-KW ✔ ✔ ✔ ✔ ✔
HMAC ✔ ✔ ✔ ✔ ✔
SHA-1 ✔
SHA-256 ✔
SHA-384 ✔
SHA-512 ✔
HKDF ✔ ✔ ✔
PBKDF2 ✔ ✔ ✔

RSASSA-PKCS1-v1_5

Description

The "`RSASSA-PKCS1-v1_5`" algorithm identifier is used to perform signing and verification using the RSASSA-PKCS1-v1_5 algorithm specified in [[RFC3447]] and using the SHA hash functions defined in this specification.

Other specifications may specify the use of additional hash algorithms with RSASSA-PKCS1-v1_5. Such specifications must define the digest operations for the additional hash algorithms and key import steps and key export steps for RSASSA-PKCS1-v1_5.

Registration

The [= recognized algorithm name =] for this algorithm is "`RSASSA-PKCS1-v1_5`".

Operation Parameters Result
sign None {{ArrayBuffer}}
verify None boolean
generateKey {{RsaHashedKeyGenParams}} {{CryptoKeyPair}}
importKey {{RsaHashedImportParams}} {{CryptoKey}}
exportKey None object

RsaKeyGenParams dictionary

dictionary RsaKeyGenParams : Algorithm {
  required [EnforceRange] unsigned long modulusLength;
  required BigInteger publicExponent;
};

The modulusLength member contains the length, in bits, of the RSA modulus.

The publicExponent member contains the RSA public exponent.

RsaHashedKeyGenParams dictionary

dictionary RsaHashedKeyGenParams : RsaKeyGenParams {
  required HashAlgorithmIdentifier hash;
};

The hash member represents the hash algorithm to use.

RsaKeyAlgorithm dictionary

dictionary RsaKeyAlgorithm : KeyAlgorithm {
  required unsigned long modulusLength;
  required BigInteger publicExponent;
};

The modulusLength member contains the length, in bits, of the RSA modulus.

The publicExponent member contains the RSA public exponent.

RsaHashedKeyAlgorithm dictionary

dictionary RsaHashedKeyAlgorithm : RsaKeyAlgorithm {
  required KeyAlgorithm hash;
};

The hash member describes the hash algorithm that is used with this key.

RsaHashedImportParams dictionary

dictionary RsaHashedImportParams : Algorithm {
  required HashAlgorithmIdentifier hash;
};

The hash member describes the hash algorithm to use.

Operations

Sign

  1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not {{KeyType/"private"}}, then [= exception/throw =] an {{InvalidAccessError}}.

  2. Perform the signature generation operation defined in Section 8.2 of [[RFC3447]] with the key represented by the {{CryptoKey/[[handle]]}} internal slot of |key| as the signer's private key and the contents of |message| as |M| and using the hash function specified in the {{RsaHashedKeyAlgorithm/hash}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| as the Hash option for the EMSA-PKCS1-v1_5 encoding method.

  3. If performing the operation results in an error, then [= exception/throw =] an {{OperationError}}.

  4. Let |signature| be the value |S| that results from performing the operation.

  5. Return the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |signature|.

Verify

  1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not "`public`", then [= exception/throw =] an {{InvalidAccessError}}.

  2. Perform the signature verification operation defined in Section 8.2 of [[RFC3447]] with the key represented by the {{CryptoKey/[[handle]]}} internal slot of |key| as the signer's RSA public key and the contents of |message| as |M| and the contents of |signature| as |S| and using the hash function specified in the {{RsaHashedKeyAlgorithm/hash}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| as the Hash option for the EMSA-PKCS1-v1_5 encoding method.

  3. Let |result| be a boolean with value true if the result of the operation was "valid signature" and the value false otherwise.

  4. Return |result|.

Generate Key

  1. If |usages| contains an entry which is not "`sign`" or "`verify`", then [= exception/throw =] a {{SyntaxError}}.

  2. Generate an RSA key pair, as defined in [[RFC3447]], with RSA modulus length equal to the {{RsaKeyGenParams/modulusLength}} attribute of |normalizedAlgorithm| and RSA public exponent equal to the {{RsaKeyGenParams/publicExponent}} attribute of |normalizedAlgorithm|.

  3. If generation of the key pair fails, then [= exception/throw =] an {{OperationError}}.

  4. Let |algorithm| be a new {{RsaHashedKeyAlgorithm}} dictionary.

  5. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`RSASSA-PKCS1-v1_5`".

  6. Set the {{RsaKeyAlgorithm/modulusLength}} attribute of |algorithm| to equal the {{RsaKeyGenParams/modulusLength}} attribute of |normalizedAlgorithm|.

  7. Set the {{RsaKeyAlgorithm/publicExponent}} attribute of |algorithm| to equal the {{RsaKeyGenParams/publicExponent}} attribute of |normalizedAlgorithm|.

  8. Set the {{RsaHashedKeyAlgorithm/hash}} attribute of |algorithm| to equal the {{RsaHashedKeyGenParams/hash}} member of |normalizedAlgorithm|.

  9. Let |publicKey| be a new {{CryptoKey}} representing the public key of the generated key pair.

  10. Set the {{CryptoKey/[[type]]}} internal slot of |publicKey| to "`public`"

  11. Set the {{CryptoKey/[[algorithm]]}} internal slot of |publicKey| to |algorithm|.

  12. Set the {{CryptoKey/[[extractable]]}} internal slot of |publicKey| to true.

  13. Set the {{CryptoKey/[[usages]]}} internal slot of |publicKey| to be the [= usage intersection =] of |usages| and `[ "verify" ]`.

  14. Let |privateKey| be a new {{CryptoKey}} representing the private key of the generated key pair.

  15. Set the {{CryptoKey/[[type]]}} internal slot of |privateKey| to {{KeyType/"private"}}

  16. Set the {{CryptoKey/[[algorithm]]}} internal slot of |privateKey| to |algorithm|.

  17. Set the {{CryptoKey/[[extractable]]}} internal slot of |privateKey| to |extractable|.

  18. Set the {{CryptoKey/[[usages]]}} internal slot of |privateKey| to be the [= usage intersection =] of |usages| and `[ "sign" ]`.

  19. Let |result| be a new {{CryptoKeyPair}} dictionary.

  20. Set the {{CryptoKeyPair/publicKey}} attribute of |result| to be |publicKey|.

  21. Set the {{CryptoKeyPair/privateKey}} attribute of |result| to be |privateKey|.

  22. Return |result|.

Import Key

  1. Let |keyData| be the key data to be imported.

  2. If |format| is {{KeyFormat/"spki"}}:

    1. If |usages| contains an entry which is not "`verify`", then [= exception/throw =] a {{SyntaxError}}.

    2. Let |spki| be the result of running the [= parse a subjectPublicKeyInfo =] algorithm over |keyData|.

    3. If an error occurred while parsing, then [= exception/throw =] a {{DataError}}.

    4. If the `algorithm` object identifier field of the `algorithm` AlgorithmIdentifier field of |spki| is not equal to the `rsaEncryption` object identifier defined in [[RFC3447]], then [= exception/throw =] a {{DataError}}.

    5. Let |publicKey| be the result of performing the [= parse an ASN.1 structure =] algorithm, with |data| as the `subjectPublicKeyInfo` field of |spki|, |structure| as the `RSAPublicKey` structure specified in Section A.1.1 of [[RFC3447]], and |exactData| set to true.

    6. If an error occurred while parsing, or it can be determined that |publicKey| is not a valid public key according to [[RFC3447]], then [= exception/throw =] a {{DataError}}.

    7. Let |key| be a new {{CryptoKey}} that represents the RSA public key identified by |publicKey|.

    8. Set the {{CryptoKey/[[type]]}} internal slot of |key| to "`public`"

    If |format| is {{KeyFormat/"pkcs8"}}:

    1. If |usages| contains an entry which is not "`sign`" then [= exception/throw =] a {{SyntaxError}}.

    2. Let |privateKeyInfo| be the result of running the [= parse a privateKeyInfo =] algorithm over |keyData|.

    3. If an error occurred while parsing, then [= exception/throw =] a {{DataError}}.

    4. If the `algorithm` object identifier field of the `privateKeyAlgorithm` PrivateKeyAlgorithm field of |privateKeyInfo| is not equal to the `rsaEncryption` object identifier defined in [[RFC3447]], then [= exception/throw =] a {{DataError}}.

    5. Let |rsaPrivateKey| be the result of performing the [= parse an ASN.1 structure =] algorithm, with |data| as the `privateKey` field of |privateKeyInfo|, |structure| as the `RSAPrivateKey` structure specified in Section A.1.2 of [[RFC3447]], and |exactData| set to true.

    6. If an error occurred while parsing, or if |rsaPrivateKey| is not a valid RSA private key according to [[RFC3447]], then [= exception/throw =] a {{DataError}}.

    7. Let |key| be a new {{CryptoKey}} that represents the RSA private key identified by |rsaPrivateKey|.

    8. Set the {{CryptoKey/[[type]]}} internal slot of |key| to {{KeyType/"private"}}

    If |format| is {{KeyFormat/"jwk"}}:
    1. If |keyData| is a {{JsonWebKey}} dictionary:

      Let |jwk| equal |keyData|.

      Otherwise:

      [= exception/Throw =] a {{DataError}}.

    2. If the {{JsonWebKey/d}} field of |jwk| is present and |usages| contains an entry which is not "`sign`", or, if the {{JsonWebKey/d}} field of |jwk| is not present and |usages| contains an entry which is not "`verify`" then [= exception/throw =] a {{SyntaxError}}.

    3. If the {{JsonWebKey/kty}} field of |jwk| is not a case-sensitive string match to "`RSA`", then [= exception/throw =] a {{DataError}}.

    4. If |usages| is non-empty and the {{JsonWebKey/use}} field of |jwk| is present and is not a case-sensitive string match to "`sig`", then [= exception/throw =] a {{DataError}}.

    5. If the {{JsonWebKey/key_ops}} field of |jwk| is present, and is invalid according to the requirements of JSON Web Key [[JWK]] or does not contain all of the specified |usages| values, then [= exception/throw =] a {{DataError}}.

    6. If the {{JsonWebKey/ext}} field of |jwk| is present and has the value false and |extractable| is true, then [= exception/throw =] a {{DataError}}.

    7. Let |hash| be a be a string whose initial value is undefined.

    8. If the {{JsonWebKey/alg}} field of |jwk| is not present:

      Let |hash| be undefined.

      If the {{JsonWebKey/alg}} field is equal to the string "`RS1`":

      Let |hash| be the string "`SHA-1`".

      If the {{JsonWebKey/alg}} field is equal to the string "`RS256`":

      Let |hash| be the string "`SHA-256`".

      If the {{JsonWebKey/alg}} field is equal to the string "`RS384`":

      Let |hash| be the string "`SHA-384`".

      If the {{JsonWebKey/alg}} field is equal to the string "`RS512`":

      Let |hash| be the string "`SHA-512`".

      Otherwise:

      1. Perform any [= RSASSA-PKCS1-v1_5 key import steps | key import steps =] defined by other applicable specifications, passing |format|, |jwk| and obtaining |hash|.

      2. If an error occurred or there are no applicable specifications, [= exception/throw =] a {{DataError}}.

    9. If |hash| is not undefined:

      1. Let |normalizedHash| be the result of normalize an algorithm with `alg` set to |hash| and `op` set to `digest`.

      2. If |normalizedHash| is not equal to the {{RsaHashedImportParams/hash}} member of |normalizedAlgorithm|, [= exception/throw =] a {{DataError}}.

    10. If the {{JsonWebKey/d}} field of |jwk| is present:

      1. If |jwk| does not meet the requirements of Section 6.3.2 of JSON Web Algorithms [[JWA]], then [= exception/throw =] a {{DataError}}.

      2. Let |privateKey| represents the RSA private key identified by interpreting |jwk| according to Section 6.3.2 of JSON Web Algorithms [[JWA]].

      3. If |privateKey| is not a valid RSA private key according to [[RFC3447]], then [= exception/throw =] a {{DataError}}.

      4. Let |key| be a new {{CryptoKey}} object that represents |privateKey|.

      5. Set the {{CryptoKey/[[type]]}} internal slot of |key| to {{KeyType/"private"}}

      Otherwise:

      1. If |jwk| does not meet the requirements of Section 6.3.1 of JSON Web Algorithms [[JWA]], then [= exception/throw =] a {{DataError}}.

      2. Let |publicKey| represent the RSA public key identified by interpreting |jwk| according to Section 6.3.1 of JSON Web Algorithms [[JWA]].

      3. If |publicKey| can be determined to not be a valid RSA public key according to [[RFC3447]], then [= exception/throw =] a {{DataError}}.

      4. Let |key| be a new {{CryptoKey}} representing |publicKey|.

      5. Set the {{CryptoKey/[[type]]}} internal slot of |key| to "`public`"

    Otherwise:
    [= exception/throw =] a {{NotSupportedError}}.

  3. Let |algorithm| be a new {{RsaHashedKeyAlgorithm}} dictionary.

  4. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`RSASSA-PKCS1-v1_5`"

  5. Set the {{RsaKeyAlgorithm/modulusLength}} attribute of |algorithm| to the length, in bits, of the RSA public modulus.

  6. Set the publicExponent attribute of |algorithm| to the BigInteger representation of the RSA public exponent.

  7. Set the {{RsaHashedKeyAlgorithm/hash}} attribute of |algorithm| to the {{RsaHashedImportParams/hash}} member of |normalizedAlgorithm|.

  8. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

  9. Return |key|.

Export Key

  1. Let |key| be the key to be exported.

  2. If the underlying cryptographic key material represented by the {{CryptoKey/[[handle]]}} internal slot of |key| cannot be accessed, then [= exception/throw =] an {{OperationError}}.

  3. If |format| is {{KeyFormat/"spki"}}

    1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not "`public`", then [= exception/throw =] an {{InvalidAccessError}}.

    2. Let |data| be an instance of the `subjectPublicKeyInfo` ASN.1 structure defined in [[RFC5280]] with the following properties:

      • Set the |algorithm| field to an `AlgorithmIdentifier` ASN.1 type with the following properties:

        • Set the |algorithm| field to the OID `rsaEncryption` defined in [[RFC3447]].

        • Set the |params| field to the ASN.1 type NULL.

      • Set the |subjectPublicKey| field to the result of DER-encoding an `RSAPublicKey` ASN.1 type, as defined in [[RFC3447]], Appendix A.1.1, that represents the RSA public key represented by the {{CryptoKey/[[handle]]}} internal slot of |key|

    3. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |data|.

    If |format| is {{KeyFormat/"pkcs8"}}:

    1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not {{KeyType/"private"}}, then [= exception/throw =] an {{InvalidAccessError}}.

    2. Let |data| be the result of encoding a privateKeyInfo structure with the following properties:

      • Set the |version| field to 0.

      • Set the |privateKeyAlgorithm| field to a `PrivateKeyAlgorithmIdentifier` ASN.1 type with the following properties:

        • Set the |algorithm| field to the OID `rsaEncryption` defined in [[RFC3447]].

        • Set the |params| field to the ASN.1 type NULL.

      • Set the |privateKey| field to the result of DER-encoding an `RSAPrivateKey` ASN.1 type, as defined in [[RFC3447]], Appendix A.1.2, that represents the RSA private key represented by the {{CryptoKey/[[handle]]}} internal slot of |key|

        [[RFC5208]] specifies that the encoding of this field should be BER encoded in Section 5 (as a "for example"). However, to avoid requiring WebCrypto implementations support BER-encoding and BER-decoding, only DER encodings are produced or accepted.

    3. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |data|.

    If |format| is {{KeyFormat/"jwk"}}:

    1. Let |jwk| be a new {{JsonWebKey}} dictionary.

    2. Set the `kty` attribute of |jwk| to the string "`RSA`".

    3. Let |hash| be the {{KeyAlgorithm/name}} attribute of the {{RsaHashedKeyAlgorithm/hash}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key|.

    4. If |hash| is "`SHA-1`":

      Set the `alg` attribute of |jwk| to the string "`RS1`".

      If |hash| is "`SHA-256`":

      Set the `alg` attribute of |jwk| to the string "`RS256`".

      If |hash| is "`SHA-384`":

      Set the `alg` attribute of |jwk| to the string "`RS384`".

      If |hash| is "`SHA-512`":

      Set the `alg` attribute of |jwk| to the string "`RS512`".

      Otherwise:

      1. Perform any [= RSASSA-PKCS1-v1_5 key import steps | key export steps =] defined by other applicable specifications, passing |format|, |key| and obtaining |alg|.

      2. If an error occurred or there are no applicable specifications, [= exception/throw =] a {{NotSupportedError}}.

      3. Set the `alg` attribute of |jwk| to |alg|.

    5. Set the attributes {{JsonWebKey/n}} and {{JsonWebKey/e}} of |jwk| according to the corresponding definitions in JSON Web Algorithms [[JWA]], Section 6.3.1.

    6. If the {{CryptoKey/[[type]]}} internal slot of |key| is {{KeyType/"private"}}:

      1. Set the attributes named {{JsonWebKey/d}}, {{JsonWebKey/p}}, {{JsonWebKey/q}}, {{JsonWebKey/dp}}, {{JsonWebKey/dq}}, and {{JsonWebKey/qi}} of |jwk| according to the corresponding definitions in JSON Web Algorithms [[JWA]], Section 6.3.2.

      2. If the underlying RSA private key represented by the {{CryptoKey/[[handle]]}} internal slot of |key| is represented by more than two primes, set the attribute named {{JsonWebKey/oth}} of |jwk| according to the corresponding definition in JSON Web Algorithms [[JWA]], Section 6.3.2.7

    7. Set the `key_ops` attribute of |jwk| to the usages attribute of |key|.

    8. Set the `ext` attribute of |jwk| to the {{CryptoKey/[[extractable]]}} internal slot of |key|.

    9. Let |result| be the result of converting |jwk| to an ECMAScript Object, as defined by [[WebIDL]].

    Otherwise

    [= exception/throw =] a {{NotSupportedError}}.

  4. Return |result|.

RSA-PSS

Description

The "`RSA-PSS`" algorithm identifier is used to perform signing and verification using the RSASSA-PSS algorithm specified in [[RFC3447]], using the SHA hash functions defined in this specification and the mask generation formula MGF1.

Other specifications may specify the use of additional hash algorithms with RSASSA-PSS. Such specifications must define the digest operation for the additional hash algorithms and key import steps and key export steps for RSASSA-PSS.

Registration

The [= recognized algorithm name =] for this algorithm is "`RSA-PSS`".

Operation Parameters Result
sign {{RsaPssParams}} {{ArrayBuffer}}
verify {{RsaPssParams}} boolean
generateKey {{RsaHashedKeyGenParams}} {{CryptoKeyPair}}
importKey {{RsaHashedImportParams}} {{CryptoKey}}
exportKey None object

RsaPssParams dictionary

dictionary RsaPssParams : Algorithm {
  required [EnforceRange] unsigned long saltLength;
};

The saltLength member represents the desired length of the random salt.

Operations

Sign

  1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not {{KeyType/"private"}}, then [= exception/throw =] an {{InvalidAccessError}}.

  2. Perform the signature generation operation defined in Section 8.1 of [[RFC3447]] with the key represented by the {{CryptoKey/[[handle]]}} internal slot of |key| as the signer's private key, |K|, and the contents of |message| as the message to be signed, |M|, and using the hash function specified by the {{RsaHashedKeyAlgorithm/hash}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| as the Hash option, MGF1 (defined in Section B.2.1 of [[RFC3447]]) as the MGF option and the saltLength member of |normalizedAlgorithm| as the salt length option for the EMSA-PSS-ENCODE operation.

  3. If performing the operation results in an error, then [= exception/throw =] an {{OperationError}}.

  4. Let |signature| be the signature, S, that results from performing the operation.

  5. Return the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |signature|.

Verify

  1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not "`public`", then [= exception/throw =] an {{InvalidAccessError}}.

  2. Perform the signature verification operation defined in Section 8.1 of [[RFC3447]] with the key represented by the {{CryptoKey/[[handle]]}} internal slot of |key| as the signer's RSA public key and the contents of |message| as |M| and the contents of |signature| as |S| and using the hash function specified by the {{RsaHashedKeyAlgorithm/hash}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| as the Hash option, MGF1 (defined in Section B.2.1 of [[RFC3447]]) as the MGF option and the saltLength member of |normalizedAlgorithm| as the salt length option for the EMSA-PSS-VERIFY operation.

  3. Let |result| be a boolean with the value true if the result of the operation was "valid signature" and the value false otherwise.

Generate Key

  1. If |usages| contains an entry which is not "`sign`" or "`verify`", then [= exception/throw =] a {{SyntaxError}}.

  2. Generate an RSA key pair, as defined in [[RFC3447]], with RSA modulus length equal to the {{RsaKeyGenParams/modulusLength}} member of |normalizedAlgorithm| and RSA public exponent equal to the {{RsaKeyGenParams/publicExponent}} member of |normalizedAlgorithm|.

  3. If performing the operation results in an error, then [= exception/throw =] an {{OperationError}}.

  4. Let |algorithm| be a new {{RsaHashedKeyAlgorithm}} dictionary.

  5. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`RSA-PSS`".

  6. Set the {{RsaKeyAlgorithm/modulusLength}} attribute of |algorithm| to equal the {{RsaKeyGenParams/modulusLength}} member of |normalizedAlgorithm|.

  7. Set the {{RsaKeyAlgorithm/publicExponent}} attribute of |algorithm| to equal the {{RsaKeyGenParams/publicExponent}} member of |normalizedAlgorithm|.

  8. Set the {{RsaHashedKeyAlgorithm/hash}} attribute of |algorithm| to equal the {{RsaHashedKeyGenParams/hash}} member of |normalizedAlgorithm|.

  9. Let |publicKey| be a new {{CryptoKey}} representing the public key of the generated key pair.

  10. Set the {{CryptoKey/[[type]]}} internal slot of |publicKey| to "`public`"

  11. Set the {{CryptoKey/[[algorithm]]}} internal slot of |publicKey| to |algorithm|.

  12. Set the {{CryptoKey/[[extractable]]}} internal slot of |publicKey| to true.

  13. Set the {{CryptoKey/[[usages]]}} internal slot of |publicKey| to be the [= usage intersection =] of |usages| and `[ "verify" ]`.

  14. Let |privateKey| be a new {{CryptoKey}} representing the private key of the generated key pair.

  15. Set the {{CryptoKey/[[type]]}} internal slot of |privateKey| to {{KeyType/"private"}}

  16. Set the {{CryptoKey/[[algorithm]]}} internal slot of |privateKey| to |algorithm|.

  17. Set the {{CryptoKey/[[extractable]]}} internal slot of |privateKey| to |extractable|.

  18. Set the {{CryptoKey/[[usages]]}} internal slot of |privateKey| to be the [= usage intersection =] of |usages| and `[ "sign" ]`.

  19. Let |result| be a new {{CryptoKeyPair}} dictionary.

  20. Set the {{CryptoKeyPair/publicKey}} attribute of |result| to |publicKey|.

  21. Set the {{CryptoKeyPair/privateKey}} attribute of |result| to |privateKey|.

  22. Return the result of converting |result| to an ECMAScript Object, as defined by [[WebIDL]].

Import Key

  1. Let |keyData| be the key data to be imported.

  2. If |format| is {{KeyFormat/"spki"}}:

    1. If |usages| contains an entry which is not "`verify`" then [= exception/throw =] a {{SyntaxError}}.

    2. Let |spki| be the result of running the [= parse a subjectPublicKeyInfo =] algorithm over |keyData|.

    3. If an error occurred while parsing, then [= exception/throw =] a {{DataError}}.

    4. If the `algorithm` object identifier field of the `algorithm` AlgorithmIdentifier field of |spki| is not equal to the `rsaEncryption` object identifier defined in [[RFC3447]], then [= exception/throw =] a {{DataError}}.

    5. Let |publicKey| be the result of performing the [= parse an ASN.1 structure =] algorithm, with |data| as the `subjectPublicKeyInfo` field of |spki|, |structure| as the `RSAPublicKey` structure specified in Section A.1.1 of [[RFC3447]], and |exactData| set to true.

    6. If an error occurred while parsing, or it can be determined that |publicKey| is not a valid public key according to [[RFC3447]], then [= exception/throw =] a {{DataError}}.

    7. Let |key| be a new {{CryptoKey}} that represents the RSA public key identified by |publicKey|.

    8. Set the {{CryptoKey/[[type]]}} internal slot of |key| to "`public`"

    If |format| is {{KeyFormat/"pkcs8"}}:

    1. If |usages| contains an entry which is not "`sign`" then [= exception/throw =] a {{SyntaxError}}.

    2. Let |privateKeyInfo| be the result of running the [= parse a privateKeyInfo =] algorithm over |keyData|.

    3. If an error occurred while parsing, then [= exception/throw =] a {{DataError}}.

    4. If the `algorithm` object identifier field of the `privateKeyAlgorithm` PrivateKeyAlgorithm field of |privateKeyInfo| is not equal to the `rsaEncryption` object identifier defined in [[RFC3447]], then [= exception/throw =] a {{DataError}}.

    5. Let |rsaPrivateKey| be the result of performing the [= parse an ASN.1 structure =] algorithm, with |data| as the `privateKey` field of |privateKeyInfo|, |structure| as the `RSAPrivateKey` structure specified in Section A.1.2 of [[RFC3447]], and |exactData| set to true.

    6. If an error occurred while parsing, or if |rsaPrivateKey| is not a valid RSA private key according to [[RFC3447]], then [= exception/throw =] a {{DataError}}.

    7. Let |key| be a new {{CryptoKey}} that represents the RSA private key identified by |rsaPrivateKey|.

    8. Set the {{CryptoKey/[[type]]}} internal slot of |key| to {{KeyType/"private"}}

    If |format| is {{KeyFormat/"jwk"}}:
    1. If |keyData| is a {{JsonWebKey}} dictionary:

      Let |jwk| equal |keyData|.

      Otherwise:

      [= exception/throw =] a {{DataError}}.

    2. If the {{JsonWebKey/d}} field of |jwk| is present and |usages| contains an entry which is not "`sign`", or, if the {{JsonWebKey/d}} field of |jwk| is not present and |usages| contains an entry which is not "`verify`" then [= exception/throw =] a {{SyntaxError}}.

    3. If the {{JsonWebKey/kty}} field of |jwk| is not a case-sensitive string match to "`RSA`", then [= exception/throw =] a {{DataError}}.

    4. If |usages| is non-empty and the {{JsonWebKey/use}} field of |jwk| is present and is not a case-sensitive string match to "`sig`", then [= exception/throw =] a {{DataError}}.

    5. If the {{JsonWebKey/key_ops}} field of |jwk| is present, and is invalid according to the requirements of JSON Web Key [[JWK]] or does not contain all of the specified |usages| values, then [= exception/throw =] a {{DataError}}.

    6. If the {{JsonWebKey/ext}} field of |jwk| is present and has the value false and |extractable| is true, then [= exception/throw =] a {{DataError}}.

    7. If the {{JsonWebKey/alg}} field of |jwk| is not present:

      Let |hash| be undefined.

      If the {{JsonWebKey/alg}} field is equal to the string "`PS1`":

      Let |hash| be the string "`SHA-1`".

      If the {{JsonWebKey/alg}} field is equal to the string "`PS256`":

      Let |hash| be the string "`SHA-256`".

      If the {{JsonWebKey/alg}} field is equal to the string "`PS384`":

      Let |hash| be the string "`SHA-384`".

      If the {{JsonWebKey/alg}} field is equal to the string "`PS512`":

      Let |hash| be the string "`SHA-512`".

      Otherwise:

      1. Perform any [= RSA-PSS key import steps | key import steps =] defined by other applicable specifications, passing |format|, |jwk| and obtaining |hash|.

      2. If an error occurred or there are no applicable specifications, [= exception/throw =] a {{DataError}}.

    8. If |hash| is not undefined:

      1. Let |normalizedHash| be the result of normalize an algorithm with `alg` set to |hash| and `op` set to `digest`.

      2. If |normalizedHash| is not equal to the {{RsaHashedImportParams/hash}} member of |normalizedAlgorithm|, [= exception/throw =] a {{DataError}}.

    9. If the {{JsonWebKey/d}} field of |jwk| is present:

      1. If |jwk| does not meet the requirements of Section 6.3.2 of JSON Web Algorithms [[JWA]], then [= exception/throw =] a {{DataError}}.

      2. Let |privateKey| represent the RSA public key identified by interpreting |jwk| according to Section 6.3.1 of JSON Web Algorithms [[JWA]].

      3. If |privateKey| can be determined to not be a valid RSA public key according to [[RFC3447]], then [= exception/throw =] a {{DataError}}.

      4. Let |key| be a new {{CryptoKey}} representing |privateKey|.

      5. Set the {{CryptoKey/[[type]]}} internal slot of |key| to {{KeyType/"private"}}

      Otherwise:

      1. If |jwk| does not meet the requirements of Section 6.3.1 of JSON Web Algorithms [[JWA]], then [= exception/throw =] a {{DataError}}.

      2. Let |publicKey| represent the RSA public key identified by interpreting |jwk| according to Section 6.3.1 of JSON Web Algorithms [[JWA]].

      3. If |publicKey| can be determined to not be a valid RSA public key according to [[RFC3447]], then [= exception/throw =] a {{DataError}}.

      4. Let |key| be a new {{CryptoKey}} representing |publicKey|.

      5. Set the {{CryptoKey/[[type]]}} internal slot of |key| to "`public`"

    Otherwise:
    [= exception/throw =] a {{NotSupportedError}}.

  3. Let |algorithm| be a new {{RsaHashedKeyAlgorithm}} dictionary.

  4. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`RSA-PSS`"

  5. Set the {{RsaKeyAlgorithm/modulusLength}} attribute of |algorithm| to the length, in bits, of the RSA public modulus.

  6. Set the {{RsaKeyAlgorithm/publicExponent}} attribute of |algorithm| to the {{BigInteger}} representation of the RSA public exponent.

  7. Set the {{RsaHashedKeyAlgorithm/hash}} attribute of |algorithm| to the {{RsaHashedImportParams/hash}} member of |normalizedAlgorithm|.

  8. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|

  9. Return |key|.

Export Key

  1. Let |key| be the key to be exported.

  2. If the underlying cryptographic key material represented by the {{CryptoKey/[[handle]]}} internal slot of |key| cannot be accessed, then [= exception/throw =] an {{OperationError}}.

  3. If |format| is {{KeyFormat/"spki"}}

    1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not "`public`", then [= exception/throw =] an {{InvalidAccessError}}.

    2. Let |data| be an instance of the `subjectPublicKeyInfo` ASN.1 structure defined in [[RFC5280]] with the following properties:

      • Set the |algorithm| field to an `AlgorithmIdentifier` ASN.1 type with the following properties:

        • Set the |algorithm| field to the OID `rsaEncryption` defined in [[RFC3447]].

        • Set the |params| field to the ASN.1 type NULL.

      • Set the |subjectPublicKey| field to the result of DER-encoding an `RSAPublicKey` ASN.1 type, as defined in [[RFC3447]], Appendix A.1.1, that represents the RSA public key represented by the {{CryptoKey/[[handle]]}} internal slot of |key|

    3. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |data|.

    If |format| is {{KeyFormat/"pkcs8"}}:

    1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not {{KeyType/"private"}}, then [= exception/throw =] an {{InvalidAccessError}}.

    2. Let |data| be the result of encoding a privateKeyInfo structure with the following properties:

      • Set the |version| field to 0.

      • Set the |privateKeyAlgorithm| field to an `PrivateKeyAlgorithmIdentifier` ASN.1 type with the following properties:

        • Set the |algorithm| field to the OID `rsaEncryption` defined in [[RFC3447]].

        • Set the |params| field to the ASN.1 type NULL.

      • Set the |privateKey| field to the result of DER-encoding an `RSAPrivateKey` ASN.1 type, as defined in [[RFC3447]], Appendix A.1.2, that represents the RSA private key represented by the {{CryptoKey/[[handle]]}} internal slot of |key|

        [[RFC5208]] specifies that the encoding of this field should be BER encoded in Section 5 (as a "for example"). However, to avoid requiring WebCrypto implementations support BER-encoding and BER-decoding, only DER encodings are produced or accepted.

    3. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |data|.

    If |format| is {{KeyFormat/"jwk"}}:

    1. Let |jwk| be a new {{JsonWebKey}} dictionary.

    2. Set the `kty` attribute of |jwk| to the string "`RSA`".

    3. Let |hash| be the {{KeyAlgorithm/name}} attribute of the {{RsaHashedKeyAlgorithm/hash}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key|.

    4. If |hash| is "`SHA-1`":

      Set the `alg` attribute of |jwk| to the string "`PS1`".

      If |hash| is "`SHA-256`":

      Set the `alg` attribute of |jwk| to the string "`PS256`".

      If |hash| is "`SHA-384`":

      Set the `alg` attribute of |jwk| to the string "`PS384`".

      If |hash| is "`SHA-512`":

      Set the `alg` attribute of |jwk| to the string "`PS512`".

      Otherwise:

      1. Perform any [= RSA-PSS key export steps | key export steps =] defined by other applicable specifications, passing |format| and the {{RsaHashedKeyAlgorithm/hash}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| and obtaining |alg|.

      2. Set the `alg` attribute of |jwk| to |alg|.

    5. Set the attributes {{JsonWebKey/n}} and {{JsonWebKey/e}} of |jwk| according to the corresponding definitions in JSON Web Algorithms [[JWA]], Section 6.3.1.

    6. If the {{CryptoKey/[[type]]}} internal slot of |key| is {{KeyType/"private"}}:

      1. Set the attributes named {{JsonWebKey/d}}, {{JsonWebKey/p}}, {{JsonWebKey/q}}, {{JsonWebKey/dp}}, {{JsonWebKey/dq}}, and {{JsonWebKey/qi}} of |jwk| according to the corresponding definitions in JSON Web Algorithms [[JWA]], Section 6.3.2.

      2. If the underlying RSA private key represented by the {{CryptoKey/[[handle]]}} internal slot of |key| is represented by more than two primes, set the attribute named {{JsonWebKey/oth}} of |jwk| according to the corresponding definition in JSON Web Algorithms [[JWA]], Section 6.3.2.7

    7. Set the `key_ops` attribute of |jwk| to the {{CryptoKey/usages}} attribute of |key|.

    8. Set the `ext` attribute of |jwk| to the {{CryptoKey/[[extractable]]}} internal slot of |key|.

    9. Let |result| be the result of converting |jwk| to an ECMAScript Object, as defined by [[WebIDL]].

    Otherwise

    [= exception/throw =] a {{NotSupportedError}}.

  4. Return |result|.

RSA-OAEP

Description

The "`RSA-OAEP`" algorithm identifier is used to perform encryption and decryption ordering to the RSAES-OAEP algorithm specified in [[RFC3447]], using the SHA hash functions defined in this specification and using the mask generation function MGF1.

Other specifications may specify the use of additional hash algorithms with RSAES-OAEP. Such specifications must define the digest operation for the additional hash algorithm and key import steps and key export steps for RSAES-OAEP.

Registration

The [= recognized algorithm name =] for this algorithm is "`RSA-OAEP`".

Operation Parameters Result
encrypt {{RsaOaepParams}} {{ArrayBuffer}}
decrypt {{RsaOaepParams}} {{ArrayBuffer}}
generateKey {{RsaHashedKeyGenParams}} {{CryptoKeyPair}}
importKey {{RsaHashedImportParams}} {{CryptoKey}}
exportKey None object

RsaOaepParams dictionary

dictionary RsaOaepParams : Algorithm {
  BufferSource label;
};

The label member represents the optional label/application data to associate with the message.

Operations

Encrypt

  1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not "`public`", then [= exception/throw =] an {{InvalidAccessError}}.

  2. Let |label| be the contents of the {{RsaOaepParams/label}} member of |normalizedAlgorithm| or the empty octet string if the {{RsaOaepParams/label}} member of |normalizedAlgorithm| is not present.

  3. Perform the encryption operation defined in Section 7.1 of [[RFC3447]] with the key represented by |key| as the recipient's RSA public key, the contents of |plaintext| as the message to be encrypted, |M| and |label| as the label, |L|, and with the hash function specified by the {{RsaHashedKeyAlgorithm/hash}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| as the Hash option and MGF1 (defined in Section B.2.1 of [[RFC3447]]) as the MGF option.

  4. If performing the operation results in an error, then [= exception/throw =] an {{OperationError}}.

  5. Let |ciphertext| be the value |C| that results from performing the operation.

  6. Return the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |ciphertext|.

Decrypt

  1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not {{KeyType/"private"}}, then [= exception/throw =] an {{InvalidAccessError}}.

  2. Let |label| be the contents of the {{RsaOaepParams/label}} member of |normalizedAlgorithm| or the empty octet string if the {{RsaOaepParams/label}} member of |normalizedAlgorithm| is not present.

  3. Perform the decryption operation defined in Section 7.1 of [[RFC3447]] with the key represented by |key| as the recipient's RSA private key, the contents of |ciphertext| as the ciphertext to be decrypted, C, and |label| as the label, |L|, and with the hash function specified by the {{RsaHashedKeyAlgorithm/hash}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| as the Hash option and MGF1 (defined in Section B.2.1 of [[RFC3447]]) as the MGF option.

  4. If performing the operation results in an error, then [= exception/throw =] an {{OperationError}}.

  5. Let |plaintext| the value |M| that results from performing the operation.

  6. Return the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |plaintext|.

Generate Key

  1. If |usages| contains an entry which is not "`encrypt`", "`decrypt`", "`wrapKey`" or "`unwrapKey`", then [= exception/throw =] a {{SyntaxError}}.

  2. Generate an RSA key pair, as defined in [[RFC3447]], with RSA modulus length equal to the {{RsaKeyGenParams/modulusLength}} member of |normalizedAlgorithm| and RSA public exponent equal to the {{RsaKeyGenParams/publicExponent}} member of |normalizedAlgorithm|.

  3. If performing the operation results in an error, then [= exception/throw =] an {{OperationError}}.

  4. Let |algorithm| be a new {{RsaHashedKeyAlgorithm}} object.

  5. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`RSA-OAEP`".

  6. Set the {{RsaKeyAlgorithm/modulusLength}} attribute of |algorithm| to equal the {{RsaKeyGenParams/modulusLength}} member of |normalizedAlgorithm|.

  7. Set the {{RsaKeyAlgorithm/publicExponent}} attribute of |algorithm| to equal the {{RsaKeyGenParams/publicExponent}} member of |normalizedAlgorithm|.

  8. Set the {{RsaHashedKeyAlgorithm/hash}} attribute of |algorithm| to equal the {{RsaHashedKeyGenParams/hash}} member of |normalizedAlgorithm|.

  9. Let |publicKey| be a new {{CryptoKey}} representing the public key of the generated key pair.

  10. Set the {{CryptoKey/[[type]]}} internal slot of |publicKey| to "`public`"

  11. Set the {{CryptoKey/[[algorithm]]}} internal slot of |publicKey| to |algorithm|.

  12. Set the {{CryptoKey/[[extractable]]}} internal slot of |publicKey| to true.

  13. Set the {{CryptoKey/[[usages]]}} internal slot of |publicKey| to be the [= usage intersection =] of |usages| and `[ "encrypt", "wrapKey" ]`.

  14. Let |privateKey| be a new {{CryptoKey}} representing the private key of the generated key pair.

  15. Set the {{CryptoKey/[[type]]}} internal slot of |privateKey| to {{KeyType/"private"}}

  16. Set the {{CryptoKey/[[algorithm]]}} internal slot of |privateKey| to |algorithm|.

  17. Set the {{CryptoKey/[[extractable]]}} internal slot of |privateKey| to |extractable|.

  18. Set the {{CryptoKey/[[usages]]}} internal slot of |privateKey| to be the [= usage intersection =] of |usages| and `[ "decrypt", "unwrapKey" ]`.

  19. Let |result| be a new {{CryptoKeyPair}} dictionary.

  20. Set the {{CryptoKeyPair/publicKey}} attribute of |result| to be |publicKey|.

  21. Set the {{CryptoKeyPair/privateKey}} attribute of |result| to be |privateKey|.

  22. Return the result of converting |result| to an ECMAScript Object, as defined by [[WebIDL]].

Import Key

  1. Let |keyData| be the key data to be imported.

  2. If |format| is {{KeyFormat/"spki"}}:

    1. If |usages| contains an entry which is not "`encrypt`" or "`wrapKey`", then [= exception/throw =] a {{SyntaxError}}.

    2. Let |spki| be the result of running the [= parse a subjectPublicKeyInfo =] algorithm over |keyData|.

    3. If an error occurred while parsing, then [= exception/throw =] a {{DataError}}.

    4. If the `algorithm` object identifier field of the `algorithm` AlgorithmIdentifier field of |spki| is not equal to the `rsaEncryption` object identifier defined in [[RFC3447]], then [= exception/throw =] a {{DataError}}.

    5. Let |publicKey| be the result of performing the [= parse an ASN.1 structure =] algorithm, with |data| as the `subjectPublicKeyInfo` field of |spki|, |structure| as the `RSAPublicKey` structure specified in Section A.1.1 of [[RFC3447]], and |exactData| set to true.

    6. If an error occurred while parsing, or it can be determined that |publicKey| is not a valid public key according to [[RFC3447]], then [= exception/throw =] a {{DataError}}.

    7. Let |key| be a new {{CryptoKey}} that represents the RSA public key identified by |publicKey|.

    8. Set the {{CryptoKey/[[type]]}} internal slot of |key| to "`public`"

    If |format| is {{KeyFormat/"pkcs8"}}:

    1. If |usages| contains an entry which is not "`decrypt`" or "`unwrapKey`", then [= exception/throw =] a {{SyntaxError}}.

    2. Let |privateKeyInfo| be the result of running the [= parse a privateKeyInfo =] algorithm over |keyData|.

    3. If an error occurred while parsing, then [= exception/throw =] a {{DataError}}.

    4. If the `algorithm` object identifier field of the `privateKeyAlgorithm` PrivateKeyAlgorithm field of |privateKeyInfo| is not equal to the `rsaEncryption` object identifier defined in [[RFC3447]], then [= exception/throw =] a {{DataError}}.

    5. Let |rsaPrivateKey| be the result of performing the [= parse an ASN.1 structure =] algorithm, with |data| as the `privateKey` field of |privateKeyInfo|, |structure| as the `RSAPrivateKey` structure specified in Section A.1.2 of [[RFC3447]], and |exactData| set to true.

    6. If an error occurred while parsing, or if |rsaPrivateKey| is not a valid RSA private key according to [[RFC3447]], then [= exception/throw =] a {{DataError}}.

    7. Let |key| be a new {{CryptoKey}} that represents the RSA private key identified by |rsaPrivateKey|.

    8. Set the {{CryptoKey/[[type]]}} internal slot of |key| to {{KeyType/"private"}}

    If |format| is {{KeyFormat/"jwk"}}:
    1. If |keyData| is a {{JsonWebKey}} dictionary:

      Let |jwk| equal |keyData|.

      Otherwise:

      [= exception/Throw =] a {{DataError}}.

    2. If the {{JsonWebKey/d}} field of |jwk| is present and |usages| contains an entry which is not "`decrypt`" or "`unwrapKey`", then [= exception/throw =] a {{SyntaxError}}.

    3. If the {{JsonWebKey/d}} field of |jwk| is not present and |usages| contains an entry which is not "`encrypt`" or "`wrapKey`", then [= exception/throw =] a {{SyntaxError}}.

    4. If the {{JsonWebKey/kty}} field of |jwk| is not a case-sensitive string match to "`RSA`", then [= exception/throw =] a {{DataError}}.

    5. If |usages| is non-empty and the {{JsonWebKey/use}} field of |jwk| is present and is not a case-sensitive string match to "`enc`", then [= exception/throw =] a {{DataError}}.

    6. If the {{JsonWebKey/key_ops}} field of |jwk| is present, and is invalid according to the requirements of JSON Web Key [[JWK]] or does not contain all of the specified |usages| values, then [= exception/throw =] a {{DataError}}.

    7. If the {{JsonWebKey/ext}} field of |jwk| is present and has the value false and |extractable| is true, then [= exception/throw =] a {{DataError}}.

    8. If the `alg` field of |jwk| is not present:
      Let |hash| be undefined.
      If the `alg` field of |jwk| is equal to "`RSA-OAEP`":
      Let |hash| be the string "`SHA-1`".
      If the `alg` field of |jwk| is equal to "`RSA-OAEP-256`":
      Let |hash| be the string "`SHA-256`".
      If the `alg` field of |jwk| is equal to "`RSA-OAEP-384`":
      Let |hash| be the string "`SHA-384`".
      If the `alg` field of |jwk| is equal to "`RSA-OAEP-512`":
      Let |hash| be the string "`SHA-512`".
      Otherwise:

      1. Perform any [= RSA-OAEP key import steps | key import steps =] defined by other applicable specifications, passing |format|, |jwk| and obtaining |hash|.

      2. If an error occurred or there are no applicable specifications, [= exception/throw =] a {{DataError}}.

    9. If |hash| is not undefined:

      1. Let |normalizedHash| be the result of normalize an algorithm with `alg` set to |hash| and `op` set to `digest`.

      2. If |normalizedHash| is not equal to the {{RsaHashedImportParams/hash}} member of |normalizedAlgorithm|, [= exception/throw =] a {{DataError}}.

    10. If the {{JsonWebKey/d}} field of |jwk| is present:

      1. If |jwk| does not meet the requirements of Section 6.3.2 of JSON Web Algorithms [[JWA]], then [= exception/throw =] a {{DataError}}.

      2. Let |privateKey| represent the RSA public key identified by interpreting |jwk| according to Section 6.3.1 of JSON Web Algorithms [[JWA]].

      3. If |privateKey| can be determined to not be a valid RSA public key according to [[RFC3447]], then [= exception/throw =] a {{DataError}}.

      4. Let |key| be a new {{CryptoKey}} representing |privateKey|.

      5. Set the {{CryptoKey/[[type]]}} internal slot of |key| to {{KeyType/"private"}}

      Otherwise:

      1. If |jwk| does not meet the requirements of Section 6.3.1 of JSON Web Algorithms [[JWA]], then [= exception/throw =] a {{DataError}}.

      2. Let |publicKey| represent the RSA public key identified by interpreting |jwk| according to Section 6.3.1 of JSON Web Algorithms [[JWA]].

      3. If |publicKey| can be determined to not be a valid RSA public key according to [[RFC3447]], then [= exception/throw =] a {{DataError}}.

      4. Let |key| be a new {{CryptoKey}} representing |publicKey|.

      5. Set the {{CryptoKey/[[type]]}} internal slot of |key| to "`public`"

    Otherwise:
    [= exception/throw =] a {{NotSupportedError}}.

  3. Let |algorithm| be a new {{RsaHashedKeyAlgorithm}}.

  4. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`RSA-OAEP`"

  5. Set the {{RsaKeyAlgorithm/modulusLength}} attribute of |algorithm| to the length, in bits, of the RSA public modulus.

  6. Set the {{RsaKeyAlgorithm/publicExponent}} attribute of |algorithm| to the {{BigInteger}} representation of the RSA public exponent.

  7. Set the {{RsaHashedKeyAlgorithm/hash}} attribute of |algorithm| to the {{RsaHashedImportParams/hash}} member of |normalizedAlgorithm|.

  8. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|

  9. Return |key|.

Export Key

  1. Let |key| be the key to be exported.

  2. If the underlying cryptographic key material represented by the {{CryptoKey/[[handle]]}} internal slot of |key| cannot be accessed, then [= exception/throw =] an {{OperationError}}.

  3. If |format| is {{KeyFormat/"spki"}}

    1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not "`public`", then [= exception/throw =] an {{InvalidAccessError}}.

    2. Let |data| be an instance of the `subjectPublicKeyInfo` ASN.1 structure defined in [[RFC5280]] with the following properties:

      • Set the |algorithm| field to an `AlgorithmIdentifier` ASN.1 type with the following properties:

        • Set the |algorithm| field to the OID `rsaEncryption` defined in [[RFC3447]].

        • Set the |params| field to the ASN.1 type NULL.

      • Set the |subjectPublicKey| field to the result of DER-encoding an `RSAPublicKey` ASN.1 type, as defined in [[RFC3447]], Appendix A.1.1, that represents the RSA public key represented by the {{CryptoKey/[[handle]]}} internal slot of |key|

    3. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |data|.

    If |format| is {{KeyFormat/"pkcs8"}}:

    1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not {{KeyType/"private"}}, then [= exception/throw =] an {{InvalidAccessError}}.

    2. Let |data| be the result of encoding a privateKeyInfo structure with the following properties:

      • Set the |version| field to 0.

      • Set the |privateKeyAlgorithm| field to an `PrivateKeyAlgorithmIdentifier` ASN.1 type with the following properties:

        • Set the |algorithm| field to the OID `rsaEncryption` defined in [[RFC3447]].

        • Set the |params| field to the ASN.1 type NULL.

      • Set the |privateKey| field to the result of DER-encoding an `RSAPrivateKey` ASN.1 type, as defined in [[RFC3447]], Appendix A.1.2, that represents the RSA private key represented by the {{CryptoKey/[[handle]]}} internal slot of |key|

        [[RFC5208]] specifies that the encoding of this field should be BER encoded in Section 5 (as a "for example"). However, to avoid requiring WebCrypto implementations support BER-encoding and BER-decoding, only DER encodings are produced or accepted.

    3. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |data|.

    If |format| is {{KeyFormat/"jwk"}}:

    1. Let |jwk| be a new {{JsonWebKey}} dictionary.

    2. Set the `kty` attribute of |jwk| to the string "`RSA`".

    3. Let |hash| be the {{KeyAlgorithm/name}} attribute of the {{RsaHashedKeyAlgorithm/hash}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key|.

    4. If |hash| is "`SHA-1`":

      Set the `alg` attribute of |jwk| to the string "`RSA-OAEP`".

      If |hash| is "`SHA-256`":

      Set the `alg` attribute of |jwk| to the string "`RSA-OAEP-256`".

      If |hash| is "`SHA-384`":

      Set the `alg` attribute of |jwk| to the string "`RSA-OAEP-384`".

      If |hash| is "`SHA-512`":

      Set the `alg` attribute of |jwk| to the string "`RSA-OAEP-512`".

      Otherwise:

      1. Perform any [= RSA-OAEP key export steps | key export steps =] defined by other applicable specifications, passing |format| and the {{RsaHashedKeyAlgorithm/hash}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| and obtaining |alg|.

      2. Set the `alg` attribute of |jwk| to |alg|.

    5. Set the attributes {{JsonWebKey/n}} and {{JsonWebKey/e}} of |jwk| according to the corresponding definitions in JSON Web Algorithms [[JWA]], Section 6.3.1.

    6. If the {{CryptoKey/[[type]]}} internal slot of |key| is {{KeyType/"private"}}:

      1. Set the attributes named {{JsonWebKey/d}}, {{JsonWebKey/p}}, {{JsonWebKey/q}}, {{JsonWebKey/dp}}, {{JsonWebKey/dq}}, and {{JsonWebKey/qi}} of |jwk| according to the corresponding definitions in JSON Web Algorithms [[JWA]], Section 6.3.2.

      2. If the underlying RSA private key represented by the {{CryptoKey/[[handle]]}} internal slot of |key| is represented by more than two primes, set the attribute named {{JsonWebKey/oth}} of |jwk| according to the corresponding definition in JSON Web Algorithms [[JWA]], Section 6.3.2.7

    7. Set the `key_ops` attribute of |jwk| to the {{CryptoKey/usages}} attribute of |key|.

    8. Set the `ext` attribute of |jwk| to the {{CryptoKey/[[extractable]]}} internal slot of |key|.

    9. Let |result| be the result of converting |jwk| to an ECMAScript Object, as defined by [[WebIDL]].

    Otherwise

    [= exception/throw =] a {{NotSupportedError}}.

  4. Return |result|.

ECDSA

Description

The "`ECDSA`" algorithm identifier is used to perform signing and verification using the ECDSA algorithm specified in [[RFC6090]] and using the SHA hash functions and elliptic curves defined in this specification.

Other specifications may specify the use of additional elliptic curves and hash algorithms with ECDSA. To specify additional hash algorithms to be used with ECDSA, a specification must define a registered algorithm that supports the digest operation. To specify an additional elliptic curve a specification must define the curve name, ECDSA signature steps, ECDSA verification steps, ECDSA generation steps, ECDSA key import steps and ECDSA key export steps.

Registration

The [= recognized algorithm name =] for this algorithm is "`ECDSA`".

Operation Parameters Result
sign {{EcdsaParams}} {{ArrayBuffer}}
verify {{EcdsaParams}} boolean
generateKey {{EcKeyGenParams}} {{CryptoKeyPair}}
importKey {{EcKeyImportParams}} {{CryptoKey}}
exportKey None object

EcdsaParams dictionary

dictionary EcdsaParams : Algorithm {
  required HashAlgorithmIdentifier hash;
};

The hash member represents the hash algorithm to use.

EcKeyGenParams dictionary

typedef DOMString NamedCurve;

dictionary EcKeyGenParams : Algorithm {
  required NamedCurve namedCurve;
};

The NamedCurve type represents named elliptic curves, which are a convenient way to specify the domain parameters of well-known elliptic curves. The following values defined by this specification:

"`P-256`"
NIST recommended curve P-256, also known as `secp256r1`.
"`P-384`"
NIST recommended curve P-384, also known as `secp384r1`.
"`P-521`"
NIST recommended curve P-521, also known as `secp521r1`.

Other specifications may define additional values.

The namedCurve member of the {{EcKeyGenParams}} dictionary represents a named curve.

EcKeyAlgorithm dictionary

dictionary EcKeyAlgorithm : KeyAlgorithm {
  required NamedCurve namedCurve;
};

The namedCurve member represents the named curve that the key uses.

EcKeyImportParams dictionary

dictionary EcKeyImportParams : Algorithm {
  required NamedCurve namedCurve;
};

The namedCurve member represents a named curve.

Operations

Sign
When signing, the following algorithm should be used:

  1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not {{KeyType/"private"}}, then [= exception/throw =] an {{InvalidAccessError}}.

  2. Let |hashAlgorithm| be the {{EcdsaParams/hash}} member of |normalizedAlgorithm|.

  3. Let |M| be the result of performing the digest operation specified by |hashAlgorithm| using |message|.

  4. Let |d| be the ECDSA private key associated with |key|.

  5. Let |params| be the EC domain parameters associated with |key|.

  6. If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`", "`P-384`" or "`P-521`":

    1. Perform the ECDSA signing process, as specified in [[RFC6090]], Section 5.4, with |M| as the message, using |params| as the EC domain parameters, and with |d| as the private key.

    2. Let |r| and |s| be the pair of integers resulting from performing the ECDSA signing process.

    3. Let |result| be an empty [= byte sequence =].

    4. Let |n| be the smallest integer such that |n| * 8 is greater than the logarithm to base 2 of the order of the base point of the elliptic curve identified by |params|.

    5. Convert |r| to an octet string of length |n| and append this sequence of bytes to |result|.

    6. Convert |s| to an octet string of length |n| and append this sequence of bytes to |result|.

    Otherwise, the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is a value specified in an applicable specification:

    Perform the [= ECDSA signature steps =] specified in that specification, passing in |M|, |params| and |d| and resulting in |result|.

  7. Return the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |result|.

Verify
When verifying, the following algorithm should be used:

  1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not "`public`", then [= exception/throw =] an {{InvalidAccessError}}.

  2. Let |hashAlgorithm| be the {{EcdsaParams/hash}} member of |normalizedAlgorithm|.

  3. Let |M| be the result of performing the digest operation specified by |hashAlgorithm| using |message|.

  4. Let |Q| be the ECDSA public key associated with |key|.

  5. Let |params| be the EC domain parameters associated with |key|.

  6. If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`", "`P-384`" or "`P-521`":

    Perform the ECDSA verifying process, as specified in [[RFC6090]], Section 5.3, with |M| as the received message, |signature| as the received signature and using |params| as the EC domain parameters, and |Q| as the public key.

    Otherwise, the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is a value specified in an applicable specification:

    Perform the [= ECDSA verification steps =] specified in that specification passing in |M|, |signature|, |params| and |Q| and resulting in an indication of whether or not the purported signature is valid.

  7. Let |result| be a boolean with the value `true` if the signature is valid and the value `false` otherwise.

  8. Return |result|.

Generate Key

  1. If |usages| contains a value which is not one of "`sign`" or "`verify`", then [= exception/throw =] a {{SyntaxError}}.

  2. If the {{EcKeyGenParams/namedCurve}} member of |normalizedAlgorithm| is "`P-256`", "`P-384`" or "`P-521`":

    Generate an Elliptic Curve key pair, as defined in [[RFC6090]] with domain parameters for the curve identified by the {{EcKeyGenParams/namedCurve}} member of |normalizedAlgorithm|.

    If the {{EcKeyGenParams/namedCurve}} member of |normalizedAlgorithm| is a value specified in an applicable specification:

    Perform the [=ECDSA generation steps =] specified in that specification, passing in |normalizedAlgorithm| and resulting in an elliptic curve key pair.

    Otherwise:

    [= exception/throw =] a {{NotSupportedError}}

  3. If performing the key generation operation results in an error, then [= exception/throw =] an {{OperationError}}.

  4. Let |algorithm| be a new {{EcKeyAlgorithm}} object.

  5. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`ECDSA`".

  6. Set the {{EcKeyAlgorithm/namedCurve}} attribute of |algorithm| to equal the {{namedCurve}} member of |normalizedAlgorithm|.

  7. Let |publicKey| be a new {{CryptoKey}} representing the public key of the generated key pair.

  8. Set the {{CryptoKey/[[type]]}} internal slot of |publicKey| to "`public`"

  9. Set the {{CryptoKey/[[algorithm]]}} internal slot of |publicKey| to |algorithm|.

  10. Set the {{CryptoKey/[[extractable]]}} internal slot of |publicKey| to true.

  11. Set the {{CryptoKey/[[usages]]}} internal slot of |publicKey| to be the [= usage intersection =] of |usages| and `[ "verify" ]`.

  12. Let |privateKey| be a new {{CryptoKey}} representing the private key of the generated key pair.

  13. Set the {{CryptoKey/[[type]]}} internal slot of |privateKey| to {{KeyType/"private"}}

  14. Set the {{CryptoKey/[[algorithm]]}} internal slot of |privateKey| to |algorithm|.

  15. Set the {{CryptoKey/[[extractable]]}} internal slot of |privateKey| to |extractable|.

  16. Set the {{CryptoKey/[[usages]]}} internal slot of |privateKey| to be the [= usage intersection =] of |usages| and `[ "sign" ]`.

  17. Let |result| be a new {{CryptoKeyPair}} dictionary.

  18. Set the {{CryptoKeyPair/publicKey}} attribute of |result| to be |publicKey|.

  19. Set the {{CryptoKeyPair/privateKey}} attribute of |result| to be |privateKey|.

  20. Return the result of converting |result| to an ECMAScript Object, as defined by [[WebIDL]].

Import Key

  1. Let |keyData| be the key data to be imported.

  2. If |format| is {{KeyFormat/"spki"}}:

    1. If |usages| contains a value which is not "`verify`" then [= exception/throw =] a {{SyntaxError}}.

    2. Let |spki| be the result of running the [= parse a subjectPublicKeyInfo =] algorithm over |keyData|

    3. If an error occurred while parsing, then [= exception/throw =] a {{DataError}}.

    4. If the `algorithm` object identifier field of the `algorithm` AlgorithmIdentifier field of |spki| is not equal to the `id-ecPublicKey` object identifier defined in [[RFC5480]], then [= exception/throw =] a {{DataError}}.

    5. If the `parameters` field of the `algorithm` AlgorithmIdentifier field of |spki| is absent, then [= exception/throw =] a {{DataError}}.

    6. Let |params| be the `parameters` field of the `algorithm` AlgorithmIdentifier field of |spki|.

    7. If |params| is not an instance of the `ECParameters` ASN.1 type defined in [[RFC5480]] that specifies a `namedCurve`, then [= exception/throw =] a {{DataError}}.

    8. Let |namedCurve| be a string whose initial value is undefined.

    9. If |params| is equivalent to the `secp256r1` object identifier defined in [[RFC5480]]:

      Set |namedCurve| "`P-256`".

      If |params| is equivalent to the `secp384r1` object identifier defined in [[RFC5480]]:

      Set |namedCurve| "`P-384`".

      If |params| is equivalent to the `secp521r1` object identifier defined in [[RFC5480]]:

      Set |namedCurve| "`P-521`".

    10. If |namedCurve| is not undefined:

      1. Let |publicKey| be the Elliptic Curve public key identified by performing the conversion steps defined in Section 2.3.4 of [[SEC1]] using the `subjectPublicKey` field of |spki|.

        The uncompressed point format MUST be supported.

      2. If the implementation does not support the compressed point format and a compressed point is provided, [= exception/throw =] a {{DataError}}.

      3. If a decode error occurs or an identity point is found, [= exception/throw =] a {{DataError}}.

      4. Let |key| be a new {{CryptoKey}} that represents |publicKey|.

      Otherwise:

      1. Perform any [= ECDSA key import steps | key import steps =] defined by other applicable specifications, passing |format|, |spki| and obtaining |namedCurve| and |key|.

      2. If an error occurred or there are no applicable specifications, [= exception/throw =] a {{DataError}}.

    11. If |namedCurve| is defined, and not equal to the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm|, [= exception/throw =] a {{DataError}}.

    12. If the public key value is not a valid point on the Elliptic Curve identified by the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm| [= exception/throw =] a {{DataError}}.

    13. Set the {{CryptoKey/[[type]]}} internal slot of |key| to "`public`"

    14. Let |algorithm| be a new {{EcKeyAlgorithm}}.

    15. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`ECDSA`".

    16. Set the {{EcKeyAlgorithm/namedCurve}} attribute of |algorithm| to |namedCurve|.

    17. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

    If |format| is {{KeyFormat/"pkcs8"}}:

    1. If |usages| contains a value which is not "`sign`" then [= exception/throw =] a {{SyntaxError}}.

    2. Let |privateKeyInfo| be the result of running the [= parse a privateKeyInfo =] algorithm over |keyData|.

    3. If an error occurs while parsing, then [= exception/throw =] a {{DataError}}.

    4. If the `algorithm` object identifier field of the `privateKeyAlgorithm` PrivateKeyAlgorithm field of |privateKeyInfo| is not equal to the `id-ecPublicKey` object identifier defined in [[RFC5480]], then [= exception/throw =] a {{DataError}}.

    5. If the `parameters` field of the `privateKeyAlgorithm` PrivateKeyAlgorithmIdentifier field of |privateKeyInfo| is not present, then [= exception/throw =] a {{DataError}}.

    6. Let |params| be the `parameters` field of the `privateKeyAlgorithm` PrivateKeyAlgorithmIdentifier field of |privateKeyInfo|.

    7. If |params| is not an instance of the `ECParameters` ASN.1 type defined in [[RFC5480]] that specifies a `namedCurve`, then [= exception/throw =] a {{DataError}}.

    8. Let |namedCurve| be a string whose initial value is undefined.

    9. If |params| is equivalent to the `secp256r1` object identifier defined in [[RFC5480]]:

      Set |namedCurve| "`P-256`".

      If |params| is equivalent to the `secp384r1` object identifier defined in [[RFC5480]]:

      Set |namedCurve| "`P-384`".

      If |params| is equivalent to the `secp521r1` object identifier defined in [[RFC5480]]:

      Set |namedCurve| "`P-521`".

    10. If |namedCurve| is not undefined:

      1. Let |ecPrivateKey| be the result of performing the [= parse an ASN.1 structure =] algorithm, with |data| as the `privateKey` field of |privateKeyInfo|, |structure| as the ASN.1 `ECPrivateKey` structure specified in Section 3 of [[RFC5915]], and |exactData| set to true.

      2. If an error occurred while parsing, then [= exception/throw =] a {{DataError}}.

      3. If the `parameters` field of |ecPrivateKey| is present, and is not an instance of the `namedCurve` ASN.1 type defined in [[RFC5480]], or does not contain the same object identifier as the `parameters` field of the `privateKeyAlgorithm` PrivateKeyAlgorithmIdentifier field of |privateKeyInfo|, then [= exception/throw =] a {{DataError}}.

      4. Let |key| be a new {{CryptoKey}} that represents the Elliptic Curve private key identified by performing the conversion steps defined in Section 3 of [[RFC5915]] using |ecPrivateKey|.

      Otherwise:

      1. Perform any [= ECDSA key import steps | key import steps =] defined by other applicable specifications, passing |format|, |privateKeyInfo| and obtaining |namedCurve| and |key|.

      2. If an error occurred or there are no applicable specifications, [= exception/throw =] a {{DataError}}.

    11. If |namedCurve| is defined, and not equal to the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm|, [= exception/throw =] a {{DataError}}.

    12. If the private key value is not a valid point on the Elliptic Curve identified by the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm| [= exception/throw =] a {{DataError}}.

    13. Set the {{CryptoKey/[[type]]}} internal slot of |key| to {{KeyType/"private"}}

    14. Let |algorithm| be a new {{EcKeyAlgorithm}}.

    15. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`ECDSA`".

    16. Set the {{EcKeyAlgorithm/namedCurve}} attribute of |algorithm| to |namedCurve|.

    17. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

    If |format| is {{KeyFormat/"jwk"}}:
    1. If |keyData| is a {{JsonWebKey}} dictionary:

      Let |jwk| equal |keyData|.

      Otherwise:

      [= exception/Throw =] a {{DataError}}.

    2. If the {{JsonWebKey/d}} field is present and |usages| contains a value which is not "`sign`", or, if the {{JsonWebKey/d}} field is not present and |usages| contains a value which is not "`verify`" then [= exception/throw =] a {{SyntaxError}}.

    3. If the {{JsonWebKey/kty}} field of |jwk| is not "`EC`", then [= exception/throw =] a {{DataError}}.

    4. If |usages| is non-empty and the {{JsonWebKey/use}} field of |jwk| is present and is not "`sig`", then [= exception/throw =] a {{DataError}}.

    5. If the {{JsonWebKey/key_ops}} field of |jwk| is present, and is invalid according to the requirements of JSON Web Key [[JWK]], or it does not contain all of the specified |usages| values, then [= exception/throw =] a {{DataError}}.

    6. If the {{JsonWebKey/ext}} field of |jwk| is present and has the value false and |extractable| is true, then [= exception/throw =] a {{DataError}}.

    7. Let |namedCurve| be a string whose value is equal to the {{JsonWebKey/crv}} field of |jwk|.

    8. If |namedCurve| is not equal to the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm|, [= exception/throw =] a {{DataError}}.

    9. If |namedCurve| is equal to "`P-256`", "`P-384`" or "`P-521`":

      1. Let |algNamedCurve| be a string whose initial value is undefined.

      2. If the {{JsonWebKey/alg}} field is not present:
        Let |algNamedCurve| be undefined.
        If the {{JsonWebKey/alg}} field is equal to the string "ES256":
        Let |algNamedCurve| be the string "`P-256`".
        If the {{JsonWebKey/alg}} field is equal to the string "ES384":
        Let |algNamedCurve| be the string "`P-384`".
        If the {{JsonWebKey/alg}} field is equal to the string "ES512":
        Let |algNamedCurve| be the string "`P-521`".
        otherwise:
        [= exception/throw =] a {{DataError}}.

      3. If |algNamedCurve| is defined, and is not equal to |namedCurve|, [= exception/throw =] a {{DataError}}.

      4. If the {{JsonWebKey/d}} field is present:

        1. If |jwk| does not meet the requirements of Section 6.2.2 of JSON Web Algorithms [[JWA]], then [= exception/throw =] a {{DataError}}.

        2. Let |key| be a new {{CryptoKey}} object that represents the Elliptic Curve private key identified by interpreting |jwk| according to Section 6.2.2 of JSON Web Algorithms [[JWA]].

        3. Set the {{CryptoKey/[[type]]}} internal slot of |Key| to {{KeyType/"private"}}.

        Otherwise:

        1. If |jwk| does not meet the requirements of Section 6.2.1 of JSON Web Algorithms [[JWA]], then [= exception/throw =] a {{DataError}}.

        2. Let |key| be a new {{CryptoKey}} object that represents the Elliptic Curve public key identified by interpreting |jwk| according to Section 6.2.1 of JSON Web Algorithms [[JWA]].

        3. Set the {{CryptoKey/[[type]]}} internal slot of |Key| to "`public`".

      Otherwise:

      1. Perform any [= ECDSA key import steps | key import steps =] defined by other applicable specifications, passing |format|, |jwk| and obtaining |key|.

      2. If an error occurred or there are no applicable specifications, [= exception/throw =] a {{DataError}}.

    10. If the key value is not a valid point on the Elliptic Curve identified by the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm| [= exception/throw =] a {{DataError}}.

    11. Let |algorithm| be a new instance of an {{EcKeyAlgorithm}} object.

    12. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`ECDSA`".

    13. Set the {{EcKeyAlgorithm/namedCurve}} attribute of |algorithm| to |namedCurve|.

    14. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

    If |format| is {{KeyFormat/"raw"}}:

    1. If the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm| is not a named curve, then [= exception/throw =] a {{DataError}}.

    2. If |usages| contains a value which is not "`verify`" then [= exception/throw =] a {{SyntaxError}}.

    3. If |namedCurve| is "`P-256`", "`P-384`" or "`P-521`":

      1. Let |Q| be the elliptic curve point on the curve identified by the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm| identified by performing the conversion steps defined in Section 2.3.4 of [[SEC1]] on |keyData|.

        The uncompressed point format MUST be supported.

      2. If the implementation does not support the compressed point format and a compressed point is provided, [= exception/throw =] a {{DataError}}.

      3. If a decode error occurs or an identity point is found, [= exception/throw =] a {{DataError}}.

      4. Let |key| be a new {{CryptoKey}} that represents |Q|.

      Otherwise:

      1. Perform any [= ECDH key import steps | key import steps =] defined by other applicable specifications, passing |format|, |keyData| and obtaining |key|.

      2. If an error occurred or there are no applicable specifications, [= exception/throw =] a {{DataError}}.

    4. Let |algorithm| be a new {{EcKeyAlgorithm}} object.

    5. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`ECDSA`".

    6. Set the {{EcKeyAlgorithm/namedCurve}} attribute of |algorithm| to equal the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm|.

    7. Set the {{CryptoKey/[[type]]}} internal slot of |key| to "`public`"

    8. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

    Otherwise:

    [= exception/throw =] a {{NotSupportedError}}.

  3. Return |key|

Export Key

  1. Let |key| be the {{CryptoKey}} to be exported.

  2. If the underlying cryptographic key material represented by the {{CryptoKey/[[handle]]}} internal slot of |key| cannot be accessed, then [= exception/throw =] an {{OperationError}}.

  3. If |format| is {{KeyFormat/"spki"}}:

    1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not "`public`", then [= exception/throw =] an {{InvalidAccessError}}.

    2. Let |data| be an instance of the `subjectPublicKeyInfo` ASN.1 structure defined in [[RFC5280]] with the following properties:

      • Set the |algorithm| field to an `AlgorithmIdentifier` ASN.1 type with the following properties:

        • Set the |algorithm| field to the OID `id-ecPublicKey` defined in [[RFC5480]].

        • Set the |parameters| field to an instance of the `ECParameters` ASN.1 type defined in [[RFC5480]] as follows:

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`", "`P-384`" or "`P-521`":

          Let |keyData| be the [= octet string =] that represents the Elliptic Curve public key represented by the {{CryptoKey/[[handle]]}} internal slot of |key| according to the encoding rules specified in Section 2.2 of [[RFC5480]] and using the uncompressed form. and |keyData|.

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`":

          Set |parameters| to the `namedCurve` choice with value equal to the object identifier `secp256r1` defined in [[RFC5480]]

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-384`":

          Set |parameters| to the `namedCurve` choice with value equal to the object identifier `secp384r1` defined in [[RFC5480]]

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-521`":

          Set |parameters| to the `namedCurve` choice with value equal to the object identifier `secp521r1` defined in [[RFC5480]]

          Otherwise:

          1. Perform any [= ECDSA key export steps | key export steps =] defined by other applicable specifications, passing |format| and the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| and obtaining |namedCurveOid| and |keyData|.

          2. Set |parameters| to the `namedCurve` choice with value equal to the object identifier |namedCurveOid|.

      • Set the |subjectPublicKey| field to |keyData|.

    3. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |data|.

    If |format| is {{KeyFormat/"pkcs8"}}:

    1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not {{KeyType/"private"}}, then [= exception/throw =] an {{InvalidAccessError}}.

    2. Let |data| be an instance of the `privateKeyInfo` ASN.1 structure defined in [[RFC5280]] with the following properties:

      • Set the |version| field to `0`.

      • Set the |privateKeyAlgorithm| field to an `PrivateKeyAlgorithmIdentifier` ASN.1 type with the following properties:

        • Set the |algorithm| field to the OID `id-ecPublicKey` defined in [[RFC5480]].

        • Set the |parameters| field to an instance of the `ECParameters` ASN.1 type defined in [[RFC5480]] as follows:

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`", "`P-384`" or "`P-521`":

          Let |keyData| be the result of DER-encoding an instance of the `ECPrivateKey` structure defined in Section 3 of [[RFC5915]] for the Elliptic Curve private key represented by the {{CryptoKey/[[handle]]}} internal slot of |key| and that conforms to the following:

          • The |parameters| field is present, and is equivalent to the |parameters| field of the |privateKeyAlgorithm| field of this `PrivateKeyInfo` ASN.1 structure.

          • The |publicKey| field is present and represents the Elliptic Curve public key associated with the Elliptic Curve private key represented by the {{CryptoKey/[[handle]]}} internal slot of |key|.

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`":

          Set |parameters| to the `namedCurve` choice with value equal to the object identifier `secp256r1` defined in [[RFC5480]]

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-384`":

          Set |parameters| to the `namedCurve` choice with value equal to the object identifier `secp384r1` defined in [[RFC5480]]

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-521`":

          Set |parameters| to the `namedCurve` choice with value equal to the object identifier `secp521r1` defined in [[RFC5480]]

          Otherwise:

          1. Perform any [= ECDSA key export steps | key export steps =] defined by other applicable specifications, passing |format| and the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| and obtaining |namedCurveOid| and |keyData|.

          2. Set |parameters| to the `namedCurve` choice with value equal to the object identifier |namedCurveOid|.

      • Set the |privateKey| field to |keyData|.

    3. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |data|.

    If |format| is {{KeyFormat/"jwk"}}:

    1. Let |jwk| be a new {{JsonWebKey}} dictionary.

    2. Set the `kty` attribute of |jwk| to "`EC`".

    3. If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`", "`P-384`" or "`P-521`":
      1. If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`":
        Set the {{JsonWebKey/crv}} attribute of |jwk| to "`P-256`"
        If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-384`":
        Set the {{JsonWebKey/crv}} attribute of |jwk| to "`P-384`"
        If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-521`":
        Set the {{JsonWebKey/crv}} attribute of |jwk| to "`P-521`"

      2. Set the {{JsonWebKey/x}} attribute of |jwk| according to the definition in Section 6.2.1.2 of JSON Web Algorithms [[JWA]].

      3. Set the {{JsonWebKey/y}} attribute of |jwk| according to the definition in Section 6.2.1.3 of JSON Web Algorithms [[JWA]].

      4. If the {{CryptoKey/[[type]]}} internal slot of |key| is {{KeyType/"private"}}

        Set the {{JsonWebKey/d}} attribute of |jwk| according to the definition in Section 6.2.2.1 of JSON Web Algorithms [[JWA]].

      Otherwise:

      1. Perform any [= ECDSA key export steps | key export steps =] defined by other applicable specifications, passing |format| and the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| and obtaining |namedCurve| and a new value of |jwk|.

      2. Set the {{JsonWebKey/crv}} attribute of |jwk| to |namedCurve|.

    4. Set the `key_ops` attribute of |jwk| to the {{CryptoKey/usages}} attribute of |key|.

    5. Set the `ext` attribute of |jwk| to the {{CryptoKey/[[extractable]]}} internal slot of |key|.

    6. Let |result| be the result of converting |jwk| to an ECMAScript Object, as defined by [[WebIDL]].

    If |format| is {{KeyFormat/"raw"}}:

    1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not "`public`", then [= exception/throw =] an {{InvalidAccessError}}.

    2. If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`", "`P-384`" or "`P-521`":

      Let |data| be an [= octet string =] representing the Elliptic Curve point |Q| represented by {{CryptoKey/[[handle]]}} internal slot of |key| according to [[SEC1]] 2.3.3 using the uncompressed format.

      Otherwise:

      Perform any [= ECDH key export steps | key export steps =] defined by other applicable specifications, passing |format| and the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| and obtaining |namedCurve| and |data|.

    3. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |data|.

    Otherwise:

    [= exception/throw =] a {{NotSupportedError}}.

  4. Return |result|.

ECDH

Description

This describes using Elliptic Curve Diffie-Hellman (ECDH) for key generation and key agreement, as specified by [[RFC6090]].

Other specifications may specify the use of additional elliptic curves with ECDH. To specify an additional elliptic curve a specification must define the curve name, ECDH generation steps, ECDH derivation steps, ECDH key import steps and ECDH key export steps.

Registration

The [= recognized algorithm name =] for this algorithm is "`ECDH`".

Operation Parameters Result
generateKey {{EcKeyGenParams}} {{CryptoKeyPair}}
deriveBits {{EcdhKeyDeriveParams}} [= octet string =]
importKey {{EcKeyImportParams}} {{CryptoKey}}
exportKey None object

EcdhKeyDeriveParams dictionary

dictionary EcdhKeyDeriveParams : Algorithm {
  required CryptoKey public;
};

The public member represents the peer's EC public key.

Operations

Generate Key

  1. If |usages| contains an entry which is not "`deriveKey`" or "`deriveBits`" then [= exception/throw =] a {{SyntaxError}}.

  2. If the {{EcKeyGenParams/namedCurve}} member of |normalizedAlgorithm| is "`P-256`", "`P-384`" or "`P-521`":

    Generate an Elliptic Curve key pair, as defined in [[RFC6090]] with domain parameters for the curve identified by the {{EcKeyGenParams/namedCurve}} member of |normalizedAlgorithm|.

    If the {{EcKeyGenParams/namedCurve}} member of |normalizedAlgorithm| is a value specified in an applicable specification that specifies the use of that value with ECDH:

    Perform the [= ECDH generation steps =] specified in that specification, passing in |normalizedAlgorithm| and resulting in an elliptic curve key pair.

    Otherwise:

    [= exception/throw =] a {{NotSupportedError}}

  3. If performing the operation results in an error, then [= exception/throw =] a {{OperationError}}.

  4. Let |algorithm| be a new {{EcKeyAlgorithm}} object.

  5. Set the {{Algorithm/name}} member of |algorithm| to "`ECDH`".

  6. Set the {{EcKeyAlgorithm/namedCurve}} attribute of |algorithm| to equal the {{namedCurve}} member of |normalizedAlgorithm|.

  7. Let |publicKey| be a new {{CryptoKey}} representing the public key of the generated key pair.

  8. Set the {{CryptoKey/[[type]]}} internal slot of |publicKey| to "`public`"

  9. Set the {{CryptoKey/[[algorithm]]}} internal slot of |publicKey| to |algorithm|.

  10. Set the {{CryptoKey/[[extractable]]}} internal slot of |publicKey| to true.

  11. Set the {{CryptoKey/[[usages]]}} internal slot of |publicKey| to be the empty list.

  12. Let |privateKey| be a new {{CryptoKey}} representing the private key of the generated key pair.

  13. Set the {{CryptoKey/[[type]]}} internal slot of |privateKey| to {{KeyType/"private"}}

  14. Set the {{CryptoKey/[[algorithm]]}} internal slot of |privateKey| to |algorithm|.

  15. Set the {{CryptoKey/[[extractable]]}} internal slot of |privateKey| to |extractable|.

  16. Set the {{CryptoKey/[[usages]]}} internal slot of |privateKey| to be the [= usage intersection =] of |usages| and `[ "deriveKey", "deriveBits" ]`.

  17. Let |result| be a new {{CryptoKeyPair}} dictionary.

  18. Set the {{CryptoKeyPair/publicKey}} attribute of |result| to be |publicKey|.

  19. Set the {{CryptoKeyPair/privateKey}} attribute of |result| to be |privateKey|.

  20. Return the result of converting |result| to an ECMAScript Object, as defined by [[WebIDL]].

Derive Bits

  1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not {{KeyType/"private"}}, then [= exception/throw =] an {{InvalidAccessError}}.

  2. Let |publicKey| be the {{EcdhKeyDeriveParams/public}} member of |normalizedAlgorithm|.

  3. If the {{CryptoKey/[[type]]}} internal slot of |publicKey| is not "`public`", then [= exception/throw =] an {{InvalidAccessError}}.

  4. If the {{KeyAlgorithm/name}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |publicKey| is not equal to the {{KeyAlgorithm/name}} property of the {{CryptoKey/[[algorithm]]}} internal slot of |key|, then [= exception/throw =] an {{InvalidAccessError}}.

  5. If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |publicKey| is not equal to the {{EcKeyAlgorithm/namedCurve}} property of the {{CryptoKey/[[algorithm]]}} internal slot of |key|, then [= exception/throw =] an {{InvalidAccessError}}.

  6. If the {{EcKeyAlgorithm/namedCurve}} property of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`", "`P-384`" or "`P-521`":

    1. Perform the ECDH primitive specified in [[RFC6090]] Section 4 with |key| as the EC private key |d| and the EC public key represented by the {{CryptoKey/[[handle]]}} internal slot of |publicKey| as the EC public key.

    2. Let |secret| be the result of applying the field element to [= octet string =] conversion defined in Section 6.2 of [[RFC6090]] to the output of the ECDH primitive.

    If the {{EcKeyAlgorithm/namedCurve}} property of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is a value specified in an applicable specification that specifies the use of that value with ECDH:

    Perform the [= ECDH derivation steps =] specified in that specification, passing in |key| and |publicKey| and resulting in |secret|.

    Otherwise:

    [= exception/throw =] a {{NotSupportedError}}

  7. If performing the operation results in an error, then [= exception/throw =] a {{OperationError}}.

  8. If |length| is null:
    Return |secret|
    Otherwise:
    If the length of |secret| in bits is less than |length|:
    [= exception/throw =] an {{OperationError}}.
    Otherwise:
    Return an [= octet string containing =] the first |length| bits of |secret|.
Import Key

  1. Let |keyData| be the key data to be imported.

  2. If |format| is {{KeyFormat/"spki"}}:

    1. If |usages| is not empty then [= exception/throw =] a {{SyntaxError}}.

    2. Let |spki| be the result of running the [= parse a subjectPublicKeyInfo =] algorithm over |keyData|

    3. If an error occurred while parsing, then [= exception/throw =] a {{DataError}}.

    4. If the `algorithm` object identifier field of the `algorithm` AlgorithmIdentifier field of |spki| is not equal to the `id-ecPublicKey` object identifier defined in [[RFC5480]], then [= exception/throw =] a {{DataError}}.

    5. If the `parameters` field of the `algorithm` AlgorithmIdentifier field of |spki| is absent, then [= exception/throw =] a {{DataError}}.

    6. Let |params| be the `parameters` field of the `algorithm` AlgorithmIdentifier field of |spki|.

    7. If |params| is not an instance of the `ECParameters` ASN.1 type defined in [[RFC5480]] that specifies a `namedCurve`, then [= exception/throw =] a {{DataError}}.

    8. Let |namedCurve| be a string whose initial value is undefined.

    9. If |params| is equivalent to the `secp256r1` object identifier defined in [[RFC5480]]:

      Set |namedCurve| "`P-256`".

      If |params| is equivalent to the `secp384r1` object identifier defined in [[RFC5480]]:

      Set |namedCurve| "`P-384`".

      If |params| is equivalent to the `secp521r1` object identifier defined in [[RFC5480]]:

      Set |namedCurve| "`P-521`".

    10. If |namedCurve| is not undefined:

      1. Let |publicKey| be the Elliptic Curve public key identified by performing the conversion steps defined in Section 2.3.4 of [[SEC1]] to the `subjectPublicKey` field of |spki|.

        The uncompressed point format MUST be supported.

      2. If the implementation does not support the compressed point format and a compressed point is provided, [= exception/throw =] a {{DataError}}.

      3. If a decode error occurs or an identity point is found, [= exception/throw =] a {{DataError}}.

      4. Let |key| be a new {{CryptoKey}} that represents |publicKey|.

      Otherwise:

      1. Perform any [= ECDH key import steps | key import steps =] defined by other applicable specifications, passing |format|, |spki| and obtaining |namedCurve| and |key|.

      2. If an error occurred or there are no applicable specifications, [= exception/throw =] a {{DataError}}.

    11. If |namedCurve| is defined, and not equal to the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm|, [= exception/throw =] a {{DataError}}.

    12. If the key value is not a valid point on the Elliptic Curve identified by the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm| [= exception/throw =] a {{DataError}}.

    13. Set the {{CryptoKey/[[type]]}} internal slot of |key| to "`public`"

    14. Let |algorithm| be a new {{EcKeyAlgorithm}}.

    15. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`ECDH`".

    16. Set the {{EcKeyAlgorithm/namedCurve}} attribute of |algorithm| to |namedCurve|.

    17. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

    If |format| is {{KeyFormat/"pkcs8"}}:

    1. If |usages| contains an entry which is not "`deriveKey`" or "`deriveBits`" then [= exception/throw =] a {{SyntaxError}}.

    2. Let |privateKeyInfo| be the result of running the [= parse a privateKeyInfo =] algorithm over |keyData|.

    3. If an error occurs while parsing, [= exception/throw =] a {{DataError}}.

    4. If the `algorithm` object identifier field of the `privateKeyAlgorithm` PrivateKeyAlgorithm field of |privateKeyInfo| is not equal to the `id-ecPublicKey` object identifier defined in [[RFC5480]], [= exception/throw =] a {{DataError}}.

    5. If the `parameters` field of the `privateKeyAlgorithm` PrivateKeyAlgorithmIdentifier field of |privateKeyInfo| is not present, [= exception/throw =] a {{DataError}}.

    6. Let |params| be the `parameters` field of the `privateKeyAlgorithm` PrivateKeyAlgorithmIdentifier field of |privateKeyInfo|.

    7. If |params| is not an instance of the `ECParameters` ASN.1 type defined in [[RFC5480]] that specifies a `namedCurve`, then [= exception/throw =] a {{DataError}}.

    8. Let |namedCurve| be a string whose initial value is undefined.

    9. If |params| is equivalent to the `secp256r1` object identifier defined in [[RFC5480]]:

      Set |namedCurve| to "`P-256`".

      If |params| is equivalent to the `secp384r1` object identifier defined in [[RFC5480]]:

      Set |namedCurve| to "`P-384`".

      If |params| is equivalent to the `secp521r1` object identifier defined in [[RFC5480]]:

      Set |namedCurve| to "`P-521`".

    10. If |namedCurve| is not undefined:

      1. Let |ecPrivateKey| be the result of performing the [= parse an ASN.1 structure =] algorithm, with |data| as the `privateKey` field of |privateKeyInfo|, |structure| as the ASN.1 `ECPrivateKey` structure specified in Section 3 of [[RFC5915]], and |exactData| set to true.

      2. If an error occurred while parsing, then [= exception/throw =] a {{DataError}}.

      3. If the `parameters` field of |ecPrivateKey| is present, and is not an instance of the `namedCurve` ASN.1 type defined in [[RFC5480]], or does not contain the same object identifier as the `parameters` field of the `privateKeyAlgorithm` PrivateKeyAlgorithmIdentifier field of |privateKeyInfo|, [= exception/throw =] a {{DataError}}.

      4. Let |key| be a new {{CryptoKey}} that represents the Elliptic Curve private key identified by performing the conversion steps defined in Section 3 of [[RFC5915]] using |ecPrivateKey|.

      Otherwise:

      1. Perform any [= ECDH key import steps | key import steps =] defined by other applicable specifications, passing |format|, |privateKeyInfo| and obtaining |namedCurve| and |key|.

      2. If an error occurred or there are no applicable specifications, [= exception/throw =] a {{DataError}}.

    11. If |namedCurve| is defined, and not equal to the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm|, [= exception/throw =] a {{DataError}}.

    12. If the key value is not a valid point on the Elliptic Curve identified by the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm| [= exception/throw =] a {{DataError}}.

    13. Set the {{CryptoKey/[[type]]}} internal slot of |key| to {{KeyType/"private"}}.

    14. Let |algorithm| be a new {{EcKeyAlgorithm}}.

    15. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`ECDH`".

    16. Set the {{EcKeyAlgorithm/namedCurve}} attribute of |algorithm| to |namedCurve|.

    17. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

    If |format| is {{KeyFormat/"jwk"}}:
    1. If |keyData| is a {{JsonWebKey}} dictionary:

      Let |jwk| equal |keyData|.

      Otherwise:

      [= exception/Throw =] a {{DataError}}.

    2. If the {{JsonWebKey/d}} field is present and if |usages| contains an entry which is not "`deriveKey`" or "`deriveBits`" then [= exception/throw =] a {{SyntaxError}}.

    3. If the {{JsonWebKey/d}} field is not present and if |usages| is not empty then [= exception/throw =] a {{SyntaxError}}.

    4. If the {{JsonWebKey/kty}} field of |jwk| is not "`EC`", then [= exception/throw =] a {{DataError}}.

    5. If |usages| is non-empty and the {{JsonWebKey/use}} field of |jwk| is present and is not equal to "`enc`" then [= exception/throw =] a {{DataError}}.

    6. If the {{JsonWebKey/key_ops}} field of |jwk| is present, and is invalid according to the requirements of JSON Web Key [[JWK]], or it does not contain all of the specified |usages| values, then [= exception/throw =] a {{DataError}}.

    7. If the {{JsonWebKey/ext}} field of |jwk| is present and has the value false and |extractable| is true, then [= exception/throw =] a {{DataError}}.

    8. Let |namedCurve| be a string whose value is equal to the {{JsonWebKey/crv}} field of |jwk|.

    9. If |namedCurve| is not equal to the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm|, [= exception/throw =] a {{DataError}}.

    10. If |namedCurve| is "`P-256`", "`P-384`" or "`P-521`":
      If the {{JsonWebKey/d}} field is present:

      1. If |jwk| does not meet the requirements of Section 6.2.2 of JSON Web Algorithms [[JWA]], then [= exception/throw =] a {{DataError}}.

      2. Let |key| be a new {{CryptoKey}} object that represents the Elliptic Curve private key identified by interpreting |jwk| according to Section 6.2.2 of JSON Web Algorithms [[JWA]].

      3. Set the {{CryptoKey/[[type]]}} internal slot of |Key| to {{KeyType/"private"}}.

      Otherwise:

      1. If |jwk| does not meet the requirements of Section 6.2.1 of JSON Web Algorithms [[JWA]], then [= exception/throw =] a {{DataError}}.

      2. Let |key| be a new {{CryptoKey}} object that represents the Elliptic Curve public key identified by interpreting |jwk| according to Section 6.2.1 of JSON Web Algorithms [[JWA]].

      3. Set the {{CryptoKey/[[type]]}} internal slot of |Key| to "`public`".

      Otherwise

      1. Perform any [= ECDH key import steps | key import steps =] defined by other applicable specifications, passing |format|, |jwk| and obtaining |key|.

      2. If an error occurred or there are no applicable specifications, [= exception/throw =] a {{DataError}}.

    11. If the key value is not a valid point on the Elliptic Curve identified by the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm| [= exception/throw =] a {{DataError}}.

    12. Let |algorithm| be a new instance of an {{EcKeyAlgorithm}} object.

    13. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`ECDH`".

    14. Set the {{EcKeyAlgorithm/namedCurve}} attribute of |algorithm| to |namedCurve|.

    15. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

    If |format| is {{KeyFormat/"raw"}}:

    1. If the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm| is not a named curve, then [= exception/throw =] a {{DataError}}.

    2. If |usages| is not the empty list, then [= exception/throw =] a {{SyntaxError}}.

    3. If |namedCurve| is "`P-256`", "`P-384`" or "`P-521`":

      1. Let |Q| be the Elliptic Curve public key on the curve identified by the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm| identified by performing the conversion steps defined in Section 2.3.4 of [[SEC1]] to |keyData|.

        The uncompressed point format MUST be supported.

      2. If the implementation does not support the compressed point format and a compressed point is provided, [= exception/throw =] a {{DataError}}.

      3. If a decode error occurs or an identity point is found, [= exception/throw =] a {{DataError}}.

      4. Let |key| be a new {{CryptoKey}} that represents |Q|.

      Otherwise:

      1. Perform any [= ECDH key import steps | key import steps =] defined by other applicable specifications, passing |format|, |keyData| and obtaining |key|.

      2. If an error occured or there are no applicable specifications, [= exception/throw =] a {{DataError}}.

    4. Let |algorithm| be a new {{EcKeyAlgorithm}} object.

    5. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`ECDH`".

    6. Set the {{EcKeyAlgorithm/namedCurve}} attribute of |algorithm| to equal the {{EcKeyImportParams/namedCurve}} member of |normalizedAlgorithm|.

    7. Set the {{CryptoKey/[[type]]}} internal slot of |key| to "`public`"

    8. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

  3. Return |key|

Export Key

  1. Let |key| be the {{CryptoKey}} to be exported.

  2. If the underlying cryptographic key material represented by the {{CryptoKey/[[handle]]}} internal slot of |key| cannot be accessed, then [= exception/throw =] an {{OperationError}}.

  3. If |format| is {{KeyFormat/"spki"}}:

    1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not "`public`", then [= exception/throw =] an {{InvalidAccessError}}.

    2. Let |data| be an instance of the `subjectPublicKeyInfo` ASN.1 structure defined in [[RFC5280]] with the following properties:

      • Set the |algorithm| field to an `AlgorithmIdentifier` ASN.1 type with the following properties:

        • Set the |algorithm| field to the OID `id-ecPublicKey` defined in [[RFC5480]].

        • Set the |parameters| field to an instance of the `ECParameters` ASN.1 type defined in [[RFC5480]] as follows:

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`", "`P-384`" or "`P-521`":

          Let |keyData| be the [= octet string =] that represents the Elliptic Curve public key represented by the {{CryptoKey/[[handle]]}} internal slot of |key| according to the encoding rules specified in Section 2.3.3 of [[SEC1]] and using the uncompressed form.

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`":

          Set |parameters| to the |namedCurve| choice with value equal to the object identifier `secp256r1` defined in [[RFC5480]]

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-384`":

          Set |parameters| to the |namedCurve| choice with value equal to the object identifier `secp384r1` defined in [[RFC5480]]

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-521`":

          Set |parameters| to the |namedCurve| choice with value equal to the object identifier `secp521r1` defined in [[RFC5480]]

          Otherwise:

          1. Perform any [= ECDH key export steps | key export steps =] defined by other applicable specifications, passing |format| and the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| and obtaining |namedCurveOid| and |keyData|.

          2. Set |parameters| to the `namedCurve` choice with value equal to the object identifier |namedCurveOid|.

      • Set the |subjectPublicKey| field to |keyData|

    If |format| is {{KeyFormat/"pkcs8"}}:

    1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not {{KeyType/"private"}}, then [= exception/throw =] an {{InvalidAccessError}}.

    2. Let |data| be an instance of the `privateKeyInfo` ASN.1 structure defined in [[RFC5280]] with the following properties:

      • Set the |version| field to `0`.

      • Set the |privateKeyAlgorithm| field to an `PrivateKeyAlgorithmIdentifier` ASN.1 type with the following properties:

        • Set the |algorithm| field to the OID `id-ecPublicKey` defined in [[RFC5480]].

        • Set the |parameters| field to an instance of the `ECParameters` ASN.1 type defined in [[RFC5480]] as follows:

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`", "`P-384`" or "`P-521`":

          Let |keyData| be the result of DER-encoding an instance of the `ECPrivateKey` structure defined in Section 3 of [[RFC5915]] for the Elliptic Curve private key represented by the {{CryptoKey/[[handle]]}} internal slot of |key| and that conforms to the following:

          • The |parameters| field is present, and is equivalent to the |parameters| field of the |privateKeyAlgorithm| field of this `PrivateKeyInfo` ASN.1 structure.

          • The |publicKey| field is present and represents the Elliptic Curve public key associated with the Elliptic Curve private key represented by the {{CryptoKey/[[handle]]}} internal slot of |key|.

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`":

          Set |parameters| to the |namedCurve| choice with value equal to the object identifier `secp256r1` defined in [[RFC5480]]

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-384`":

          Set |parameters| to the |namedCurve| choice with value equal to the object identifier `secp384r1` defined in [[RFC5480]]

          If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-521`":

          Set |parameters| to the |namedCurve| choice with value equal to the object identifier `secp521r1` defined in [[RFC5480]]

          Otherwise:

          1. Perform any [= ECDH key export steps | key export steps =] defined by other applicable specifications, passing |format| and the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| and obtaining |namedCurveOid| and |keyData|.

          2. Set |parameters| to the `namedCurve` choice with value equal to the object identifier |namedCurveOid|.

      • Set the |privateKey| field to |keyData|.

    If |format| is {{KeyFormat/"jwk"}}:

    1. Let |jwk| be a new {{JsonWebKey}} dictionary.

    2. Set the `kty` attribute of |jwk| to "`EC`".

    3. If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`", "`P-384`" or "`P-521`":
      1. If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`":
        Set the {{JsonWebKey/crv}} attribute of |jwk| to "`P-256`"
        If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-384`":
        Set the {{JsonWebKey/crv}} attribute of |jwk| to "`P-384`"
        If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-521`":
        Set the {{JsonWebKey/crv}} attribute of |jwk| to "`P-521`"

      2. Set the {{JsonWebKey/x}} attribute of |jwk| according to the definition in Section 6.2.1.2 of JSON Web Algorithms [[JWA]].

      3. Set the {{JsonWebKey/y}} attribute of |jwk| according to the definition in Section 6.2.1.3 of JSON Web Algorithms [[JWA]].

      4. If the {{CryptoKey/[[type]]}} internal slot of |key| is {{KeyType/"private"}}

        Set the {{JsonWebKey/d}} attribute of |jwk| according to the definition in Section 6.2.2.1 of JSON Web Algorithms [[JWA]].

      Otherwise:

      1. Perform any [= ECDH key export steps | key export steps =] defined by other applicable specifications, passing |format| and the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| and obtaining |namedCurve| and a new value of |jwk|.

      2. Set the {{JsonWebKey/crv}} attribute of |jwk| to |namedCurve|.

    4. Set the `key_ops` attribute of |jwk| to the {{CryptoKey/usages}} attribute of |key|.

    5. Set the `ext` attribute of |jwk| to the {{CryptoKey/[[extractable]]}} internal slot of |key|.

    6. Let |result| be the result of converting |jwk| to an ECMAScript Object, as defined by [[WebIDL]].

    If |format| is {{KeyFormat/"raw"}}:

    1. If the {{CryptoKey/[[type]]}} internal slot of |key| is not "`public`", then [= exception/throw =] an {{InvalidAccessError}}.

    2. If the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| is "`P-256`", "`P-384`" or "`P-521`":

      Let |data| be the [= octet string =] that represents the Elliptic Curve public key represented by the {{CryptoKey/[[handle]]}} internal slot of |key| according to the encoding rules specified in Section 2.3.3 of [[SEC1]] and using the uncompressed form.

      Otherwise:

      Perform any [= ECDH key export steps | key export steps =] defined by other applicable specifications, passing |format| and the {{EcKeyAlgorithm/namedCurve}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| and obtaining |namedCurve| and |data|.

    3. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |data|.

  4. Return |result|.

AES-CTR

Description

The "`AES-CTR`" algorithm identifier is used to perform encryption and decryption using AES in Counter mode, as described in [[NIST-SP800-38A]].

Registration

The [= recognized algorithm name =] for this algorithm is "`AES-CTR`".

Operation Parameters Result
encrypt {{AesCtrParams}} {{ArrayBuffer}}
decrypt {{AesCtrParams}} {{ArrayBuffer}}
generateKey {{AesKeyGenParams}} {{CryptoKey}}
importKey None {{CryptoKey}}
exportKey None object
get key length {{AesDerivedKeyParams}} Integer

AesCtrParams dictionary

dictionary AesCtrParams : Algorithm {
  required BufferSource counter;
  required [EnforceRange] octet length;
};

The counter member contains the initial value of the counter block. {{AesCtrParams/counter}} MUST be 16 bytes (the AES block size). The counter bits are the rightmost length bits of the counter block. The rest of the counter block is for the nonce. The counter bits are incremented using the standard incrementing function specified in NIST SP 800-38A Appendix B.1: the counter bits are interpreted as a big-endian integer and incremented by one.

The length member contains the length, in bits, of the rightmost part of the counter block that is incremented.

AesKeyAlgorithm dictionary

dictionary AesKeyAlgorithm : KeyAlgorithm {
  required unsigned short length;
};

The length member represents the length, in bits, of the key.

AesKeyGenParams dictionary

dictionary AesKeyGenParams : Algorithm {
  required [EnforceRange] unsigned short length;
};

The length member represents the length, in bits, of the key.

AesDerivedKeyParams dictionary

dictionary AesDerivedKeyParams : Algorithm {
  required [EnforceRange] unsigned short length;
};

The length member represents the length, in bits, of the key.

Operations

Encrypt

  1. If the {{AesCtrParams/counter}} member of |normalizedAlgorithm| does not have length 16 bytes, then [= exception/throw =] an {{OperationError}}.

  2. If the {{AesCtrParams/length}} member of |normalizedAlgorithm| is zero or is greater than 128, then [= exception/throw =] an {{OperationError}}.

  3. Let |ciphertext| be the result of performing the CTR Encryption operation described in Section 6.5 of [[NIST-SP800-38A]] using AES as the block cipher, the contents of the {{AesCtrParams/counter}} member of |normalizedAlgorithm| as the initial value of the counter block, the {{AesCtrParams/length}} member of |normalizedAlgorithm| as the input parameter |m| to the standard counter block incrementing function defined in Appendix B.1 of [[NIST-SP800-38A]] and the contents of |plaintext| as the input plaintext.

  4. Return the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |ciphertext|.

Decrypt

  1. If the {{AesCtrParams/counter}} member of |normalizedAlgorithm| does not have length 16 bytes, then [= exception/throw =] an {{OperationError}}.

  2. If the {{AesCtrParams/length}} member of |normalizedAlgorithm| is zero or is greater than 128, then [= exception/throw =] an {{OperationError}}.

  3. Let |plaintext| be the result of performing the CTR Decryption operation described in Section 6.5 of [[NIST-SP800-38A]] using AES as the block cipher, the contents of the {{AesCtrParams/counter}} member of |normalizedAlgorithm| as the initial value of the counter block, the {{AesCtrParams/length}} member of |normalizedAlgorithm| as the input parameter |m| to the standard counter block incrementing function defined in Appendix B.1 of [[NIST-SP800-38A]] and the contents of |ciphertext| as the input ciphertext.

  4. Return the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |plaintext|.

Generate Key

  1. If |usages| contains any entry which is not one of "`encrypt`", "`decrypt`", "`wrapKey`" or "`unwrapKey`", then [= exception/throw =] a {{SyntaxError}}.

  2. If the {{AesKeyGenParams/length}} member of |normalizedAlgorithm| is not equal to one of 128, 192 or 256, then [= exception/throw =] an {{OperationError}}.

  3. Generate an AES key of length equal to the {{AesKeyGenParams/length}} member of |normalizedAlgorithm|.

  4. If the key generation step fails, then [= exception/throw =] an {{OperationError}}.

  5. Let |key| be a new {{CryptoKey}} object representing the generated AES key.

  6. Let |algorithm| be a new {{AesKeyAlgorithm}}.

  7. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`AES-CTR`".

  8. Set the {{AesKeyAlgorithm/length}} attribute of |algorithm| to equal the {{AesKeyGenParams/length}} member of |normalizedAlgorithm|.

  9. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

  10. Set the {{CryptoKey/[[extractable]]}} internal slot of |key| to be |extractable|.

  11. Set the {{CryptoKey/[[usages]]}} internal slot of |key| to be |usages|.

  12. Return |key|.

Import Key

  1. If |usages| contains an entry which is not one of "`encrypt`", "`decrypt`", "`wrapKey`" or "`unwrapKey`", then [= exception/throw =] a {{SyntaxError}}.

  2. If |format| is {{KeyFormat/"raw"}}:

    1. Let |data| be the [= octet string =] contained in |keyData|.

    2. If the length in bits of |data| is not 128, 192 or 256 then [= exception/throw =] a {{DataError}}.

    If |format| is {{KeyFormat/"jwk"}}:
    1. If |keyData| is a {{JsonWebKey}} dictionary:

      Let |jwk| equal |keyData|.

      Otherwise:

      [= exception/Throw =] a {{DataError}}.

    2. If the {{JsonWebKey/kty}} field of |jwk| is not "`oct`", then [= exception/throw =] a {{DataError}}.

    3. If |jwk| does not meet the requirements of Section 6.4 of JSON Web Algorithms [[JWA]], then [= exception/throw =] a {{DataError}}.

    4. Let |data| be the [= octet string =] obtained by decoding the {{JsonWebKey/k}} field of |jwk|.

    5. If |data| has length 128 bits:
      If the {{JsonWebKey/alg}} field of |jwk| is present, and is not "`A128CTR`", then [= exception/throw =] a {{DataError}}.
      If |data| has length 192 bits:
      If the {{JsonWebKey/alg}} field of |jwk| is present, and is not "`A192CTR`", then [= exception/throw =] a {{DataError}}.
      If |data| has length 256 bits:
      If the {{JsonWebKey/alg}} field of |jwk| is present, and is not "`A256CTR`", then [= exception/throw =] a {{DataError}}.
      Otherwise:
      [= exception/throw =] a {{DataError}}.

    6. If |usages| is non-empty and the {{JsonWebKey/use}} field of |jwk| is present and is not "`enc`", then [= exception/throw =] a {{DataError}}.

    7. If the {{JsonWebKey/key_ops}} field of |jwk| is present, and is invalid according to the requirements of JSON Web Key [[JWK]] or does not contain all of the specified |usages| values, then [= exception/throw =] a {{DataError}}.

    8. If the {{JsonWebKey/ext}} field of |jwk| is present and has the value false and |extractable| is true, then [= exception/throw =] a {{DataError}}.

    Otherwise:
    [= exception/throw =] a {{NotSupportedError}}.

  3. Let |key| be a new `{{CryptoKey}}` object representing an AES key with value |data|.

  4. Let |algorithm| be a new {{AesKeyAlgorithm}}.

  5. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`AES-CTR`".

  6. Set the {{AesKeyAlgorithm/length}} attribute of |algorithm| to the length, in bits, of |data|.

  7. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

  8. Return |key|.

Export Key

  1. If the underlying cryptographic key material represented by the {{CryptoKey/[[handle]]}} internal slot of |key| cannot be accessed, then [= exception/throw =] an {{OperationError}}.

  2. If |format| is {{KeyFormat/"raw"}}:

    1. Let |data| be the raw octets of the key represented by {{CryptoKey/[[handle]]}} internal slot of |key|.

    2. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |data|.

    If |format| is {{KeyFormat/"jwk"}}:

    1. Let |jwk| be a new {{JsonWebKey}} dictionary.

    2. Set the `kty` attribute of |jwk| to the string "`oct`".

    3. Set the {{JsonWebKey/k}} attribute of |jwk| to be a string containing the raw octets of the key represented by {{CryptoKey/[[handle]]}} internal slot of |key|, encoded according to Section 6.4 of JSON Web Algorithms [[JWA]].

    4. If the {{AesKeyAlgorithm/length}} attribute of |key| is 128:
      Set the `alg` attribute of |jwk| to the string "`A128CTR`".
      If the {{AesKeyAlgorithm/length}} attribute of |key| is 192:
      Set the `alg` attribute of |jwk| to the string "`A192CTR`".
      If the {{AesKeyAlgorithm/length}} attribute of |key| is 256:
      Set the `alg` attribute of |jwk| to the string "`A256CTR`".

    5. Set the `key_ops` attribute of |jwk| to equal the {{CryptoKey/[[usages]]}} internal slot of |key|.

    6. Set the `ext` attribute of |jwk| to equal the {{CryptoKey/[[extractable]]}} internal slot of |key|.

    7. Let |result| be the result of converting |jwk| to an ECMAScript Object, as defined by [[WebIDL]].

    Otherwise:

    [= exception/throw =] a {{NotSupportedError}}.

  3. Return |result|.

Get key length

  1. If the {{AesDerivedKeyParams/length}} member of |normalizedDerivedKeyAlgorithm| is not 128, 192 or 256, then [= exception/throw =] a {{OperationError}}.

  2. Return the {{AesDerivedKeyParams/length}} member of |normalizedDerivedKeyAlgorithm|.

AES-CBC

Description

The "`AES-CBC`" algorithm identifier is used to perform encryption and decryption using AES in Cipher Block Chaining mode, as described in [[NIST-SP800-38A]].

When operating in CBC mode, messages that are not exact multiples of the AES block size (16 bytes) can be padded under a variety of padding schemes. In the Web Crypto API, the only padding mode that is supported is that of PKCS#7, as described by Section 10.3, step 2, of [[RFC2315]].

Registration

The [= recognized algorithm name =] for this algorithm is "`AES-CBC`".

Operation Parameters Result
encrypt {{AesCbcParams}} {{ArrayBuffer}}
decrypt {{AesCbcParams}} {{ArrayBuffer}}
generateKey {{AesKeyGenParams}} {{CryptoKey}}
importKey None {{CryptoKey}}
exportKey None object
get key length {{AesDerivedKeyParams}} Integer

AesCbcParams dictionary

dictionary AesCbcParams : Algorithm {
  required BufferSource iv;
};

The iv member represents the initialization vector. It MUST be 16 bytes.

Operations

Encrypt

  1. If the {{AesCbcParams/iv}} member of |normalizedAlgorithm| does not have length 16 bytes, then [= exception/throw =] an {{OperationError}}.

  2. Let |paddedPlaintext| be the result of adding padding octets to the contents of |plaintext| according to the procedure defined in Section 10.3 of [[RFC2315]], step 2, with a value of |k| of 16.

  3. Let |ciphertext| be the result of performing the CBC Encryption operation described in Section 6.2 of [[NIST-SP800-38A]] using AES as the block cipher, the contents of the {{AesCbcParams/iv}} member of |normalizedAlgorithm| as the |IV| input parameter and |paddedPlaintext| as the input plaintext.

  4. Return the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |ciphertext|.

Decrypt

  1. If the {{AesCbcParams/iv}} member of |normalizedAlgorithm| does not have length 16 bytes, then [= exception/throw =] an {{OperationError}}.

  2. Let |paddedPlaintext| be the result of performing the CBC Decryption operation described in Section 6.2 of [[NIST-SP800-38A]] using AES as the block cipher, the contents of the {{AesCbcParams/iv}} member of |normalizedAlgorithm| as the |IV| input parameter and the contents of |ciphertext| as the input ciphertext.

  3. Let |p| be the value of the last octet of |paddedPlaintext|.

  4. If |p| is zero or greater than 16, or if any of the last |p| octets of |paddedPlaintext| have a value which is not |p|, then [= exception/throw =] an {{OperationError}}.

  5. Let |plaintext| be the result of removing |p| octets from the end of |paddedPlaintext|.

  6. Return the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |plaintext|.

Generate Key

  1. If |usages| contains any entry which is not one of "`encrypt`", "`decrypt`", "`wrapKey`" or "`unwrapKey`", then [= exception/throw =] a {{SyntaxError}}.

  2. If the {{AesKeyGenParams/length}} member of |normalizedAlgorithm| is not equal to one of 128, 192 or 256, then [= exception/throw =] an {{OperationError}}.

  3. Generate an AES key of length equal to the {{AesKeyGenParams/length}} member of |normalizedAlgorithm|.

  4. If the key generation step fails, then [= exception/throw =] an {{OperationError}}.

  5. Let |key| be a new {{CryptoKey}} object representing the generated AES key.

  6. Let |algorithm| be a new {{AesKeyAlgorithm}}.

  7. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`AES-CBC`".

  8. Set the {{AesKeyAlgorithm/length}} attribute of |algorithm| to equal the {{AesKeyGenParams/length}} member of |normalizedAlgorithm|.

  9. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

  10. Set the {{CryptoKey/[[extractable]]}} internal slot of |key| to be |extractable|.

  11. Set the {{CryptoKey/[[usages]]}} internal slot of |key| to be |usages|.

  12. Return |key|.

Import Key

  1. If |usages| contains an entry which is not one of "`encrypt`", "`decrypt`", "`wrapKey`" or "`unwrapKey`", then [= exception/throw =] a {{SyntaxError}}.

  2. If |format| is {{KeyFormat/"raw"}}:

    1. Let |data| be the [= octet string =] contained in |keyData|.

    2. If the length in bits of |data| is not 128, 192 or 256 then [= exception/throw =] a {{DataError}}.

    If |format| is {{KeyFormat/"jwk"}}:
    1. If |keyData| is a {{JsonWebKey}} dictionary:

      Let |jwk| equal |keyData|.

      Otherwise:

      [= exception/Throw =] a {{DataError}}.

    2. If the {{JsonWebKey/kty}} field of |jwk| is not "`oct`", then [= exception/throw =] a {{DataError}}.

    3. If |jwk| does not meet the requirements of Section 6.4 of JSON Web Algorithms [[JWA]], then [= exception/throw =] a {{DataError}}.

    4. Let |data| be the [= octet string =] obtained by decoding the {{JsonWebKey/k}} field of |jwk|.

    5. If |data| has length 128 bits:
      If the {{JsonWebKey/alg}} field of |jwk| is present, and is not "`A128CBC`", then [= exception/throw =] a {{DataError}}.
      If |data| has length 192 bits:
      If the {{JsonWebKey/alg}} field of |jwk| is present, and is not "`A192CBC`", then [= exception/throw =] a {{DataError}}.
      If |data| has length 256 bits:
      If the {{JsonWebKey/alg}} field of |jwk| is present, and is not "`A256CBC`", then [= exception/throw =] a {{DataError}}.
      Otherwise:
      [= exception/throw =] a {{DataError}}.

    6. If |usages| is non-empty and the {{JsonWebKey/use}} field of |jwk| is present and is not "`enc`", then [= exception/throw =] a {{DataError}}.

    7. If the {{JsonWebKey/key_ops}} field of |jwk| is present, and is invalid according to the requirements of JSON Web Key [[JWK]] or does not contain all of the specified |usages| values, then [= exception/throw =] a {{DataError}}.

    8. If the {{JsonWebKey/ext}} field of |jwk| is present and has the value false and |extractable| is true, then [= exception/throw =] a {{DataError}}.

    Otherwise:
    [= exception/throw =] a {{NotSupportedError}}

  3. Let |key| be a new `{{CryptoKey}}` object representing an AES key with value |data|.

  4. Let |algorithm| be a new {{AesKeyAlgorithm}}.

  5. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`AES-CBC`".

  6. Set the {{AesKeyAlgorithm/length}} attribute of |algorithm| to the length, in bits, of |data|.

  7. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

  8. Return |key|.

Export Key

  1. If the underlying cryptographic key material represented by the {{CryptoKey/[[handle]]}} internal slot of |key| cannot be accessed, then [= exception/throw =] an {{OperationError}}.

  2. If |format| is {{KeyFormat/"raw"}}:

    1. Let |data| be the raw octets of the key represented by {{CryptoKey/[[handle]]}} internal slot of |key|.

    2. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |data|.

    If |format| is {{KeyFormat/"jwk"}}:
    1. If |keyData| is a {{JsonWebKey}} dictionary:

      Let |jwk| equal |keyData|.

      Otherwise:

      [= exception/Throw =] a {{DataError}}.

    2. Set the `kty` attribute of |jwk| to the string "`oct`".

    3. Set the {{JsonWebKey/k}} attribute of |jwk| to be a string containing the raw octets of the key represented by {{CryptoKey/[[handle]]}} internal slot of |key|, encoded according to Section 6.4 of JSON Web Algorithms [[JWA]].

    4. If the {{AesKeyAlgorithm/length}} attribute of |key| is 128:
      Set the `alg` attribute of |jwk| to the string "`A128CBC`".
      If the {{AesKeyAlgorithm/length}} attribute of |key| is 192:
      Set the `alg` attribute of |jwk| to the string "`A192CBC`".
      If the {{AesKeyAlgorithm/length}} attribute of |key| is 256:
      Set the `alg` attribute of |jwk| to the string "`A256CBC`".

    5. Set the `key_ops` attribute of |jwk| to equal the {{CryptoKey/usages}} attribute of |key|.

    6. Set the `ext` attribute of |jwk| to equal the {{CryptoKey/[[extractable]]}} internal slot of |key|.

    7. Let |result| be the result of converting |jwk| to an ECMAScript Object, as defined by [[WebIDL]].

    Otherwise:

    [= exception/throw =] a {{NotSupportedError}}.

  3. Return |result|.

Get key length

  1. If the {{AesDerivedKeyParams/length}} member of |normalizedDerivedKeyAlgorithm| is not 128, 192 or 256, then [= exception/throw =] an {{OperationError}}.

  2. Return the {{AesDerivedKeyParams/length}} member of |normalizedDerivedKeyAlgorithm|.

AES-GCM

Description

The "`AES-GCM`" algorithm identifier is used to perform authenticated encryption and decryption using AES in Galois/Counter Mode mode, as described in [[NIST-SP800-38D]].

Registration

The [= recognized algorithm name =] for this algorithm is "`AES-GCM`".

Operation Parameters Result
encrypt {{AesGcmParams}} {{ArrayBuffer}}
decrypt {{AesGcmParams}} {{ArrayBuffer}}
generateKey {{AesKeyGenParams}} {{CryptoKey}}
importKey None {{CryptoKey}}
exportKey None object
get key length {{AesDerivedKeyParams}} Integer

AesGcmParams dictionary

dictionary AesGcmParams : Algorithm {
  required BufferSource iv;
  BufferSource additionalData;
  [EnforceRange] octet tagLength;
};

The iv member represents the initialization vector to use. May be up to 2^64-1 bytes long.

The additionalData member represents the additional authentication data to include.

The tagLength member represents the desired length of the authentication tag. May be 0 - 128.

Operations

Encrypt

  1. If |plaintext| has a length greater than 2^39 - 256 bytes, then [= exception/throw =] an {{OperationError}}.

  2. If the {{AesGcmParams/iv}} member of |normalizedAlgorithm| has a length greater than 2^64 - 1 bytes, then [= exception/throw =] an {{OperationError}}.

  3. If the {{AesGcmParams/additionalData}} member of |normalizedAlgorithm| is present and has a length greater than 2^64 - 1 bytes, then [= exception/throw =] an {{OperationError}}.

  4. If the {{AesGcmParams/tagLength}} member of |normalizedAlgorithm| is not present:
    Let |tagLength| be 128.
    If the {{AesGcmParams/tagLength}} member of |normalizedAlgorithm| is one of 32, 64, 96, 104, 112, 120 or 128:
    Let |tagLength| be equal to the {{AesGcmParams/tagLength}} member of |normalizedAlgorithm|
    Otherwise:
    [= exception/throw =] an {{OperationError}}.

  5. Let |additionalData| be the contents of the {{AesGcmParams/additionalData}} member of |normalizedAlgorithm| if present or the empty octet string otherwise.

  6. Let |C| and |T| be the outputs that result from performing the Authenticated Encryption Function described in Section 7.1 of [[NIST-SP800-38D]] using AES as the block cipher, the contents of the {{AesGcmParams/iv}} member of |normalizedAlgorithm| as the |IV| input parameter, the contents of |additionalData| as the |A| input parameter, |tagLength| as the |t| pre-requisite and the contents of |plaintext| as the input plaintext.

  7. Let |ciphertext| be equal to |C| | |T|, where '|' denotes concatenation.

  8. Return the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |ciphertext|.

Decrypt
  1. If the {{AesGcmParams/tagLength}} member of |normalizedAlgorithm| is not present:
    Let |tagLength| be 128.
    If the {{AesGcmParams/tagLength}} member of |normalizedAlgorithm| is one of 32, 64, 96, 104, 112, 120 or 128:
    Let |tagLength| be equal to the {{AesGcmParams/tagLength}} member of |normalizedAlgorithm|
    Otherwise:
    [= exception/throw =] an {{OperationError}}.

  2. If |ciphertext| has a length less than |tagLength| bits, then [= exception/throw =] an {{OperationError}}.

  3. If the {{AesGcmParams/iv}} member of |normalizedAlgorithm| has a length greater than 2^64 - 1 bytes, then [= exception/throw =] an {{OperationError}}.

  4. If the {{AesGcmParams/additionalData}} member of |normalizedAlgorithm| is present and has a length greater than 2^64 - 1 bytes, then [= exception/throw =] an {{OperationError}}.

  5. Let |tag| be the last |tagLength| bits of |ciphertext|.

  6. Let |actualCiphertext| be the result of removing the last |tagLength| bits from |ciphertext|.

  7. Let |additionalData| be the contents of the {{AesGcmParams/additionalData}} member of |normalizedAlgorithm| if present or the empty octet string otherwise.

  8. Perform the Authenticated Decryption Function described in Section 7.2 of [[NIST-SP800-38D]] using AES as the block cipher, the contents of the {{AesGcmParams/iv}} member of |normalizedAlgorithm| as the |IV| input parameter, the contents of |additionalData| as the |A| input parameter, |tagLength| as the |t| pre-requisite, the contents of |actualCiphertext| as the input ciphertext, |C| and the contents of |tag| as the authentication tag, |T|.

    If the result of the algorithm is the indication of inauthenticity, "|FAIL|":
    [= exception/throw =] an {{OperationError}}
    Otherwise:
    Let |plaintext| be the output |P| of the Authenticated Decryption Function.

  9. Return the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |plaintext|.

Generate Key

  1. If |usages| contains any entry which is not one of "`encrypt`", "`decrypt`", "`wrapKey`" or "`unwrapKey`", then [= exception/throw =] a {{SyntaxError}}.

  2. If the {{AesKeyGenParams/length}} member of |normalizedAlgorithm| is not equal to one of 128, 192 or 256, then [= exception/throw =] an {{OperationError}}.

  3. Generate an AES key of length equal to the {{AesKeyGenParams/length}} member of |normalizedAlgorithm|.

  4. If the key generation step fails, then [= exception/throw =] an {{OperationError}}.

  5. Let |key| be a new {{CryptoKey}} object representing the generated AES key.

  6. Let |algorithm| be a new {{AesKeyAlgorithm}}.

  7. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`AES-GCM`".

  8. Set the {{AesKeyAlgorithm/length}} attribute of |algorithm| to equal the {{AesKeyGenParams/length}} member of |normalizedAlgorithm|.

  9. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

  10. Set the {{CryptoKey/[[extractable]]}} internal slot of |key| to be |extractable|.

  11. Set the {{CryptoKey/[[usages]]}} internal slot of |key| to be |usages|.

  12. Return |key|.

Import Key

  1. If |usages| contains an entry which is not one of "`encrypt`", "`decrypt`", "`wrapKey`" or "`unwrapKey`", then [= exception/throw =] a {{SyntaxError}}.

  2. If |format| is {{KeyFormat/"raw"}}:

    1. Let |data| be the [= octet string =] contained in |keyData|.

    2. If the length in bits of |data| is not 128, 192 or 256 then [= exception/throw =] a {{DataError}}.

    If |format| is {{KeyFormat/"jwk"}}:
    1. If |keyData| is a {{JsonWebKey}} dictionary:

      Let |jwk| equal |keyData|.

      Otherwise:

      [= exception/Throw =] a {{DataError}}.

    2. If the {{JsonWebKey/kty}} field of |jwk| is not "`oct`", then [= exception/throw =] a {{DataError}}.

    3. If |jwk| does not meet the requirements of Section 6.4 of JSON Web Algorithms [[JWA]], then [= exception/throw =] a {{DataError}}.

    4. Let |data| be the [= octet string =] obtained by decoding the {{JsonWebKey/k}} field of |jwk|.

    5. If |data| has length 128 bits:
      If the {{JsonWebKey/alg}} field of |jwk| is present, and is not "`A128GCM`", then [= exception/throw =] a {{DataError}}.
      If |data| has length 192 bits:
      If the {{JsonWebKey/alg}} field of |jwk| is present, and is not "`A192GCM`", then [= exception/throw =] a {{DataError}}.
      If |data| has length 256 bits:
      If the {{JsonWebKey/alg}} field of |jwk| is present, and is not "`A256GCM`", then [= exception/throw =] a {{DataError}}.
      Otherwise:
      [= exception/throw =] a {{DataError}}.

    6. If |usages| is non-empty and the {{JsonWebKey/use}} field of |jwk| is present and is not "`enc`", then [= exception/throw =] a {{DataError}}.

    7. If the {{JsonWebKey/key_ops}} field of |jwk| is present, and is invalid according to the requirements of JSON Web Key [[JWK]] or does not contain all of the specified |usages| values, then [= exception/throw =] a {{DataError}}.

    8. If the {{JsonWebKey/ext}} field of |jwk| is present and has the value false and |extractable| is true, then [= exception/throw =] a {{DataError}}.

    Otherwise:
    [= exception/throw =] a {{NotSupportedError}}.

  3. Let |key| be a new `{{CryptoKey}}` object representing an AES key with value |data|.

  4. Let |algorithm| be a new {{AesKeyAlgorithm}}.

  5. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`AES-GCM`".

  6. Set the {{AesKeyAlgorithm/length}} attribute of |algorithm| to the length, in bits, of |data|.

  7. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

  8. Return |key|.

Export Key

  1. If the underlying cryptographic key material represented by the {{CryptoKey/[[handle]]}} internal slot of |key| cannot be accessed, then [= exception/throw =] an {{OperationError}}.

  2. If |format| is {{KeyFormat/"raw"}}:

    1. Let |data| be the raw octets of the key represented by {{CryptoKey/[[handle]]}} internal slot of |key|.

    2. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |data|.

    If |format| is {{KeyFormat/"jwk"}}:

    1. Let |jwk| be a new {{JsonWebKey}} dictionary.

    2. Set the `kty` attribute of |jwk| to the string "`oct`".

    3. Set the {{JsonWebKey/k}} attribute of |jwk| to be a string containing the raw octets of the key represented by {{CryptoKey/[[handle]]}} internal slot of |key|, encoded according to Section 6.4 of JSON Web Algorithms [[JWA]].

    4. If the {{AesKeyAlgorithm/length}} attribute of |key| is 128:
      Set the `alg` attribute of |jwk| to the string "`A128GCM`".
      If the {{AesKeyAlgorithm/length}} attribute of |key| is 192:
      Set the `alg` attribute of |jwk| to the string "`A192GCM`".
      If the {{AesKeyAlgorithm/length}} attribute of |key| is 256:
      Set the `alg` attribute of |jwk| to the string "`A256GCM`".

    5. Set the `key_ops` attribute of |jwk| to equal the {{CryptoKey/usages}} attribute of |key|.

    6. Set the `ext` attribute of |jwk| to equal the {{CryptoKey/[[extractable]]}} internal slot of |key|.

    7. Let |result| be the result of converting |jwk| to an ECMAScript Object, as defined by [[WebIDL]].

    Otherwise:

    [= exception/throw =] a {{NotSupportedError}}.

  3. Return |result|.

Get key length

  1. If the {{AesDerivedKeyParams/length}} member of |normalizedDerivedKeyAlgorithm| is not 128, 192 or 256, then [= exception/throw =] an {{OperationError}}.

  2. Return the {{AesDerivedKeyParams/length}} member of |normalizedDerivedKeyAlgorithm|.

AES-KW

Description

The "`AES-KW`" algorithm identifier is used to perform key wrapping using AES, as described in [[RFC3394]].

Registration

The [= recognized algorithm name =] for this algorithm is "`AES-KW`".

Operation Parameters Result
wrapKey None {{ArrayBuffer}}
unwrapKey None {{ArrayBuffer}}
generateKey {{AesKeyGenParams}} {{CryptoKey}}
importKey None {{CryptoKey}}
exportKey None object
get key length {{AesDerivedKeyParams}} Integer

Operations

Wrap Key

  1. If |plaintext| is not a multiple of 64 bits in length, then [= exception/throw =] an {{OperationError}}.

  2. Let |ciphertext| be the result of performing the Key Wrap operation described in Section 2.2.1 of [[RFC3394]] with |plaintext| as the plaintext to be wrapped and using the default Initial Value defined in Section 2.2.3.1 of the same document.

  3. Return |ciphertext|.

Unwrap Key

  1. Let |plaintext| be the result of performing the Key Unwrap operation described in Section 2.2.2 of [[RFC3394]] with |ciphertext| as the input ciphertext and using the default Initial Value defined in Section 2.2.3.1 of the same document.

  2. If the Key Unwrap operation returns an error, then [= exception/throw =] an {{OperationError}}.

  3. Return |plaintext|.

Generate Key

  1. If |usages| contains any entry which is not one of "`wrapKey`" or "`unwrapKey`", then [= exception/throw =] a {{SyntaxError}}.

  2. If the {{AesKeyGenParams/length}} property of |normalizedAlgorithm| is not equal to one of 128, 192 or 256, then [= exception/throw =] an {{OperationError}}.

  3. Generate an AES key of length equal to the {{AesKeyGenParams/length}} member of |normalizedAlgorithm|.

  4. If the key generation step fails, then [= exception/throw =] an {{OperationError}}.

  5. Let |key| be a new {{CryptoKey}} object representing the generated AES key.

  6. Let |algorithm| be a new {{AesKeyAlgorithm}}.

  7. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`AES-KW`".

  8. Set the {{AesKeyAlgorithm/length}} attribute of |algorithm| to equal the {{AesKeyGenParams/length}} property of |normalizedAlgorithm|.

  9. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

  10. Set the {{CryptoKey/[[extractable]]}} internal slot of |key| to be |extractable|.

  11. Set the {{CryptoKey/[[usages]]}} internal slot of |key| to be |usages|.

  12. Return |key|.

Import Key

  1. If |usages| contains an entry which is not one of "`wrapKey`" or "`unwrapKey`", then [= exception/throw =] a {{SyntaxError}}.

  2. If |format| is {{KeyFormat/"raw"}}:

    1. Let |data| be the [= octet string =] contained in |keyData|.

    2. If the length in bits of |data| is not 128, 192 or 256 then [= exception/throw =] a {{DataError}}.

    If |format| is {{KeyFormat/"jwk"}}:
    1. If |keyData| is a {{JsonWebKey}} dictionary:

      Let |jwk| equal |keyData|.

      Otherwise:

      [= exception/Throw =] a {{DataError}}.

    2. If the {{JsonWebKey/kty}} field of |jwk| is not "`oct`", then [= exception/throw =] a {{DataError}}.

    3. If |jwk| does not meet the requirements of Section 6.4 of JSON Web Algorithms [[JWA]], then [= exception/throw =] a {{DataError}}.

    4. Let |data| be the [= octet string =] obtained by decoding the {{JsonWebKey/k}} field of |jwk|.

    5. If |data| has length 128 bits:
      If the {{JsonWebKey/alg}} field of |jwk| is present, and is not "`A128KW`", then [= exception/throw =] a {{DataError}}.
      If |data| has length 192 bits:
      If the {{JsonWebKey/alg}} field of |jwk| is present, and is not "`A192KW`", then [= exception/throw =] a {{DataError}}.
      If |data| has length 256 bits:
      If the {{JsonWebKey/alg}} field of |jwk| is present, and is not "`A256KW`", then [= exception/throw =] a {{DataError}}.
      Otherwise:
      [= exception/throw =] a {{DataError}}.

    6. If |usages| is non-empty and the {{JsonWebKey/use}} field of |jwk| is present and is not "`enc`", then [= exception/throw =] a {{DataError}}.

    7. If the {{JsonWebKey/key_ops}} field of |jwk| is present, and is invalid according to the requirements of JSON Web Key [[JWK]] or does not contain all of the specified |usages| values, then [= exception/throw =] a {{DataError}}.

    8. If the {{JsonWebKey/ext}} field of |jwk| is present and has the value false and |extractable| is true, then [= exception/throw =] a {{DataError}}.

    Otherwise:
    [= exception/throw =] a {{NotSupportedError}}.

  3. Let |key| be a new {{CryptoKey}} representing an AES key with value |data|.

  4. Let |algorithm| be a new {{AesKeyAlgorithm}}.

  5. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`AES-KW`".

  6. Set the {{AesKeyAlgorithm/length}} attribute of |algorithm| to the length, in bits, of |data|.

  7. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

  8. Return |key|.

Export Key

  1. If the underlying cryptographic key material represented by the {{CryptoKey/[[handle]]}} internal slot of |key| cannot be accessed, then [= exception/throw =] an {{OperationError}}.

  2. If |format| is {{KeyFormat/"raw"}}:

    1. Let |data| be the raw octets of the key represented by {{CryptoKey/[[handle]]}} internal slot of |key|.

    2. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |data|.

    If |format| is {{KeyFormat/"jwk"}}:

    1. Let |jwk| be a new {{JsonWebKey}} dictionary.

    2. Set the `kty` attribute of |jwk| to the string "`oct`".

    3. Set the {{JsonWebKey/k}} attribute of |jwk| to be a string containing the raw octets of the key represented by {{CryptoKey/[[handle]]}} internal slot of |key|, encoded according to Section 6.4 of JSON Web Algorithms [[JWA]].

    4. If the {{AesKeyAlgorithm/length}} attribute of |key| is 128:
      Set the `alg` attribute of |jwk| to the string "`A128KW`".
      If the {{AesKeyAlgorithm/length}} attribute of |key| is 192:
      Set the `alg` attribute of |jwk| to the string "`A192KW`".
      If the {{AesKeyAlgorithm/length}} attribute of |key| is 256:
      Set the `alg` attribute of |jwk| to the string "`A256KW`".

    5. Set the `key_ops` attribute of |jwk| to equal the {{CryptoKey/usages}} attribute of |key|.

    6. Set the `ext` attribute of |jwk| to equal the {{CryptoKey/[[extractable]]}} internal slot of |key|.

    7. Let |result| be the result of converting |jwk| to an ECMAScript Object, as defined by [[WebIDL]].

    Otherwise:

    [= exception/throw =] a {{NotSupportedError}}.

  3. Return |result|.

Get key length

  1. If the {{AesDerivedKeyParams/length}} member of |normalizedDerivedKeyAlgorithm| is not 128, 192 or 256, then [= exception/throw =] an {{OperationError}}.

  2. Return the {{AesDerivedKeyParams/length}} member of |normalizedDerivedKeyAlgorithm|.

HMAC

Description

The `HMAC` algorithm calculates and verifies hash-based message authentication codes according to [[FIPS-198-1]] using the SHA hash functions defined in this specification.

Other specifications may specify the use of additional hash algorithms with HMAC. Such specifications must define the digest operation for the additional hash algorithms and key import steps and key export steps for HMAC.

Registration

The [= recognized algorithm name =] for this algorithm is "`HMAC`".

Operation Parameters Result
sign None {{ArrayBuffer}}
verify None boolean
generateKey {{HmacKeyGenParams}} {{CryptoKey}}
importKey {{HmacImportParams}} {{CryptoKey}}
exportKey None object
get key length {{HmacImportParams}} Integer

HmacImportParams dictionary

dictionary HmacImportParams : Algorithm {
  required HashAlgorithmIdentifier hash;
  [EnforceRange] unsigned long length;
};

The hash member represents the inner hash function to use.

The length member represent the length (in bits) of the key.

HmacKeyAlgorithm dictionary

dictionary HmacKeyAlgorithm : KeyAlgorithm {
  required KeyAlgorithm hash;
  required unsigned long length;
};

The hash member represents the inner hash function to use.

The length member represent the length (in bits) of the key.

HmacKeyGenParams dictionary

dictionary HmacKeyGenParams : Algorithm {
  required HashAlgorithmIdentifier hash;
  [EnforceRange] unsigned long length;
};

The hash member represents the inner hash function to use.

The length member represent the length (in bits) of the key to generate. If unspecified, the recommended length will be used, which is the size of the associated hash function's block size.

Operations

Sign

  1. Let |mac| be the result of performing the MAC Generation operation described in Section 4 of [[FIPS-198-1]] using the key represented by {{CryptoKey/[[handle]]}} internal slot of |key|, the hash function identified by the {{HmacKeyAlgorithm/hash}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| and |message| as the input data |text|.

  2. Return the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |mac|.

Verify

  1. Let |mac| be the result of performing the MAC Generation operation described in Section 4 of [[FIPS-198-1]] using the key represented by {{CryptoKey/[[handle]]}} internal slot of |key|, the hash function identified by the {{HmacKeyAlgorithm/hash}} attribute of the {{CryptoKey/[[algorithm]]}} internal slot of |key| and |message| as the input data |text|.

  2. Return true if |mac| is equal to |signature| and false otherwise.

Generate Key

  1. If |usages| contains any entry which is not "`sign`" or "`verify`", then [= exception/throw =] a {{SyntaxError}}.

  2. If the {{HmacKeyGenParams/length}} member of |normalizedAlgorithm| is not present:
    Let |length| be the block size in bits of the hash function identified by the {{HmacKeyGenParams/hash}} member of |normalizedAlgorithm|.
    Otherwise, if the {{HmacKeyGenParams/length}} member of |normalizedAlgorithm| is non-zero:
    Let |length| be equal to the {{HmacKeyGenParams/length}} member of |normalizedAlgorithm|.
    Otherwise:
    [= exception/throw =] an {{OperationError}}.

  3. Generate a key of length |length| bits.

  4. If the key generation step fails, then [= exception/throw =] an {{OperationError}}.

  5. Let |key| be a new {{CryptoKey}} object representing the generated key.

  6. Let |algorithm| be a new {{HmacKeyAlgorithm}}.

  7. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`HMAC`".

  8. Let |hash| be a new {{KeyAlgorithm}}.

  9. Set the {{KeyAlgorithm/name}} attribute of |hash| to equal the {{Algorithm/name}} member of the {{HmacKeyGenParams/hash}} member of |normalizedAlgorithm|.

  10. Set the {{HmacKeyAlgorithm/hash}} attribute of |algorithm| to |hash|.

  11. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

  12. Set the {{CryptoKey/[[extractable]]}} internal slot of |key| to be |extractable|.

  13. Set the {{CryptoKey/[[usages]]}} internal slot of |key| to be |usages|.

  14. Return |key|.

Import Key

  1. Let |keyData| be the key data to be imported.

  2. If |usages| contains an entry which is not "`sign`" or "`verify`", then [= exception/throw =] a {{SyntaxError}}.

  3. Let |hash| be a new {{KeyAlgorithm}}.

  4. If |format| is {{KeyFormat/"raw"}}:

    1. Let |data| be the [= octet string =] contained in |keyData|.

    2. Set |hash| to equal the {{HmacImportParams/hash}} member of |normalizedAlgorithm|.

    If |format| is {{KeyFormat/"jwk"}}:
    1. If |keyData| is a {{JsonWebKey}} dictionary:

      Let |jwk| equal |keyData|.

      Otherwise:

      [= exception/Throw =] a {{DataError}}.

    2. If the {{JsonWebKey/kty}} field of |jwk| is not "`oct`", then [= exception/throw =] a {{DataError}}.

    3. If |jwk| does not meet the requirements of Section 6.4 of JSON Web Algorithms [[JWA]], then [= exception/throw =] a {{DataError}}.

    4. Let |data| be the [= octet string =] obtained by decoding the {{JsonWebKey/k}} field of |jwk|.

    5. Set the |hash| to equal the {{HmacImportParams/hash}} member of |normalizedAlgorithm|.

    6. If the {{KeyAlgorithm/name}} attribute of |hash| is "`SHA-1`":
      If the {{JsonWebKey/alg}} field of |jwk| is present and is not "`HS1`", then [= exception/throw =] a {{DataError}}.
      If the {{KeyAlgorithm/name}} attribute of |hash| is "`SHA-256`":
      If the {{JsonWebKey/alg}} field of |jwk| is present and is not "`HS256`", then [= exception/throw =] a {{DataError}}.
      If the {{KeyAlgorithm/name}} attribute of |hash| is "`SHA-384`":
      If the {{JsonWebKey/alg}} field of |jwk| is present and is not "`HS384`", then [= exception/throw =] a {{DataError}}.
      If the {{KeyAlgorithm/name}} attribute of |hash| is "`SHA-512`":
      If the {{JsonWebKey/alg}} field of |jwk| is present and is not "`HS512`", then [= exception/throw =] a {{DataError}}.
      Otherwise, if the {{KeyAlgorithm/name}} attribute of |hash| is defined in another applicable specification:
      Perform any [= HMAC key import steps | key import steps =] defined by other applicable specifications, passing |format|, |jwk| and |hash| and obtaining |hash|.

    7. If |usages| is non-empty and the {{JsonWebKey/use}} field of |jwk| is present and is not "`sign`", then [= exception/throw =] a {{DataError}}.

    8. If the {{JsonWebKey/key_ops}} field of |jwk| is present, and is invalid according to the requirements of JSON Web Key [[JWK]] or does not contain all of the specified |usages| values, then [= exception/throw =] a {{DataError}}.

    9. If the {{JsonWebKey/ext}} field of |jwk| is present and has the value false and |extractable| is true, then [= exception/throw =] a {{DataError}}.

    Otherwise:
    [= exception/throw =] a {{NotSupportedError}}.

  5. Let |length| be equivalent to the length, in octets, of |data|, multiplied by 8.

  6. If |length| is zero then [= exception/throw =] a {{DataError}}.

  7. If the {{HmacImportParams/length}} member of |normalizedAlgorithm| is present:
    If the {{HmacImportParams/length}} member of |normalizedAlgorithm| is greater than |length|:
    [= exception/throw =] a {{DataError}}.
    If the {{HmacImportParams/length}} member of |normalizedAlgorithm|, is less than or equal to |length| minus eight:
    [= exception/throw =] a {{DataError}}.
    Otherwise:
    Set |length| equal to the {{HmacImportParams/length}} member of |normalizedAlgorithm|.

  8. Let |key| be a new `{{CryptoKey}}` object representing an HMAC key with the first |length| bits of |data|.

  9. Let |algorithm| be a new {{HmacKeyAlgorithm}}.

  10. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`HMAC`".

  11. Set the {{HmacKeyAlgorithm/length}} attribute of |algorithm| to |length|.

  12. Set the {{HmacKeyAlgorithm/hash}} attribute of |algorithm| to |hash|.

  13. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

  14. Return |key|.

Export Key

  1. If the underlying cryptographic key material represented by the {{CryptoKey/[[handle]]}} internal slot of |key| cannot be accessed, then [= exception/throw =] an {{OperationError}}.

  2. Let |bits| be the raw bits of the key represented by {{CryptoKey/[[handle]]}} internal slot of |key|.

  3. Let |data| be an [= octet string containing =] |bits|.

  4. If |format| is {{KeyFormat/"raw"}}:

    1. Let |result| be the result of [= ArrayBuffer/create | creating =] an {{ArrayBuffer}} containing |data|.

    If |format| is {{KeyFormat/"jwk"}}:

    1. Let |jwk| be a new {{JsonWebKey}} dictionary.

    2. Set the `kty` attribute of |jwk| to the string "`oct`".

    3. Set the {{JsonWebKey/k}} attribute of |jwk| to be a string containing |data|, encoded according to Section 6.4 of JSON Web Algorithms [[JWA]].

    4. Let |algorithm| be the {{CryptoKey/[[algorithm]]}} internal slot of |key|.

    5. Let |hash| be the {{HmacKeyAlgorithm/hash}} attribute of |algorithm|.

    6. If the {{KeyAlgorithm/name}} attribute of |hash| is "`SHA-1`":
      Set the `alg` attribute of |jwk| to the string "`HS1`".
      If the {{KeyAlgorithm/name}} attribute of |hash| is "`SHA-256`":
      Set the `alg` attribute of |jwk| to the string "`HS256`".
      If the {{KeyAlgorithm/name}} attribute of |hash| is "`SHA-384`":
      Set the `alg` attribute of |jwk| to the string "`HS384`".
      If the {{KeyAlgorithm/name}} attribute of |hash| is "`SHA-512`":
      Set the `alg` attribute of |jwk| to the string "`HS512`".
      Otherwise, the {{KeyAlgorithm/name}} attribute of |hash| is defined in another applicable specification:

      1. Perform any [= HMAC key export steps | key export steps =] defined by other applicable specifications, passing |format| and |key| and obtaining |alg|.

      2. Set the `alg` attribute of |jwk| to |alg|.

    7. Set the `key_ops` attribute of |jwk| to equal the {{CryptoKey/usages}} attribute of |key|.

    8. Set the `ext` attribute of |jwk| to equal the {{CryptoKey/[[extractable]]}} internal slot of |key|.

    9. Let |result| be the result of converting |jwk| to an ECMAScript Object, as defined by [[WebIDL]].

    Otherwise:

    [= exception/throw =] a {{NotSupportedError}}.

  5. Return |result|.

Get key length
  1. If the {{HmacImportParams/length}} member of |normalizedDerivedKeyAlgorithm| is not present:

    Let |length| be the block size in bits of the hash function identified by the {{HmacImportParams/hash}} member of |normalizedDerivedKeyAlgorithm|.

    Otherwise, if the {{HmacImportParams/length}} member of |normalizedDerivedKeyAlgorithm| is non-zero:
    Let |length| be equal to the {{HmacImportParams/length}} member of |normalizedDerivedKeyAlgorithm|.
    Otherwise:
    [= exception/throw =] a {{TypeError}}.

  2. Return |length|.

SHA

Description

This describes the SHA-1 and SHA-2 families, as specified by [[FIPS-180-4]].

Registration

The recognized algorithm names are "SHA-1", "SHA-256", "SHA-384", and "SHA-512" for the respective SHA algorithms.

Operation Parameters Result
digest None {{ArrayBuffer}}

Operations

Digest
  1. If the {{Algorithm/name}} member of |normalizedAlgorithm| is a cases-sensitive string match for "`SHA-1`":
    Let |result| be the result of performing the SHA-1 hash function defined in Section 6.1 of [[FIPS-180-4]] using |message| as the input message, |M|.
    If the {{Algorithm/name}} member of |normalizedAlgorithm| is a cases-sensitive string match for "`SHA-256`":
    Let |result| be the result of performing the SHA-256 hash function defined in Section 6.2 of [[FIPS-180-4]] using |message| as the input message, |M|.
    If the {{Algorithm/name}} member of |normalizedAlgorithm| is a cases-sensitive string match for "`SHA-384`":
    Let |result| be the result of performing the SHA-384 hash function defined in Section 6.5 of [[FIPS-180-4]] using |message| as the input message, |M|.
    If the {{Algorithm/name}} member of |normalizedAlgorithm| is a cases-sensitive string match for "`SHA-512`":
    Let |result| be the result of performing the SHA-1 hash function defined in Section 6.4 of [[FIPS-180-4]] using |message| as the input message, |M|.

  2. If performing the operation results in an error, then [= exception/throw =] an {{OperationError}}.

  3. Return a new ArrayBuffer containing |result|.

HKDF

Description

The "`HKDF`" algorithm identifier is used to perform key derivation using the extraction-then-expansion approach described in [[RFC5869]] and using the SHA hash functions defined in this specification.

Other specifications may specify the use of additional hash algorithms with HKDF. Such specifications must define the digest operation for the additional hash algorithms.

Registration

The [= recognized algorithm name =] for this algorithm is "`HKDF`".

Operation Parameters Result
deriveBits {{HkdfParams}} {{ArrayBuffer}}
importKey None {{CryptoKey}}
Get key length None null

HkdfParams dictionary

dictionary HkdfParams : Algorithm {
  required HashAlgorithmIdentifier hash;
  required BufferSource salt;
  required BufferSource info;
};

The hash member represents the algorithm to use with HMAC (e.g.: SHA-256).

The salt member represents a bit string that corresponds to the salt used in the extract step.

The info member represents a bit string that corresponds to the context and application specific context for the derived keying material.

Operations

Derive Bits

  1. If |length| is null or zero, or is not a multiple of 8, then [= exception/throw =] an {{OperationError}}.

  2. Let |extractKey| be a key equal to |n| zero bits where |n| is the size of the output of the hash function described by the {{HkdfParams/hash}} member of |normalizedAlgorithm|.

  3. Let |keyDerivationKey| be the secret represented by {{CryptoKey/[[handle]]}} internal slot of |key| as the message.

  4. Let |result| be the result of performing the HKDF extract and then the HKDF expand step described in Section 2 of [[RFC5869]] using:

    • the {{HkdfParams/hash}} member of |normalizedAlgorithm| as |Hash|,

    • |keyDerivationKey| as the input keying material, |IKM|,

    • the contents of the {{HkdfParams/salt}} member of |normalizedAlgorithm| as |salt|,

    • the contents of the {{HkdfParams/info}} member of |normalizedAlgorithm| as |info|,

    • |length| divided by 8 as the value of |L|,

  5. If the key derivation operation fails, then [= exception/throw =] an {{OperationError}}.

  6. Return |result|.

Import key

  1. Let |keyData| be the key data to be imported.

  2. If |format| is {{KeyFormat/"raw"}}:

    1. If |usages| contains a value that is not "`deriveKey`" or "`deriveBits`", then [= exception/throw =] a {{SyntaxError}}.

    2. If |extractable| is not `false`, then [= exception/throw =] a {{SyntaxError}}.

    3. Let |key| be a new {{CryptoKey}} representing the key data provided in |keyData|.

    4. Set the {{CryptoKey/[[type]]}} internal slot of |key| to {{KeyType/"secret"}}.

    5. Set the {{CryptoKey/[[extractable]]}} internal slot of |key| to `false`.

    6. Let |algorithm| be a new {{KeyAlgorithm}} object.

    7. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`HKDF`".

    8. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

    9. Return |key|.

    Otherwise:
    [= exception/throw =] a {{NotSupportedError}}.
Get key length

  1. Return null.

PBKDF2

Description

The "`PBKDF2`" algorithm identifier is used to perform key derivation using the PKCS#5 password-based key derivation function version 2, as defined in [[RFC8018]] using HMAC as the pseudo-random function, using the SHA hash functions defined in this specification.

Other specifications may specify the use of additional hash algorithms with PBKDF2. Such specifications must define the digest operation for the additional hash algorithms.

Registration

The [= recognized algorithm name =] for this algorithm is "`PBKDF2`".

Operation Parameters Result
deriveBits {{Pbkdf2Params}} {{ArrayBuffer}}
importKey None {{CryptoKey}}
Get key length None null

Pbkdf2Params dictionary

dictionary Pbkdf2Params : Algorithm {
  required BufferSource salt;
  required [EnforceRange] unsigned long iterations;
  required HashAlgorithmIdentifier hash;
};

The {{Pbkdf2Params}} dictionary has a salt member, a iterations member, and a hash member.

Operations

Derive Bits

  1. If |length| is null or zero, or is not a multiple of 8, then [= exception/throw =] an {{OperationError}}.

  2. If the {{Pbkdf2Params/iterations}} member of |normalizedAlgorithm| is zero, then [= exception/throw =] an {{OperationError}}.

  3. Let |prf| be the MAC Generation function described in Section 4 of [[FIPS-198-1]] using the hash function described by the {{Pbkdf2Params/hash}} member of |normalizedAlgorithm|.

  4. Let |result| be the result of performing the PBKDF2 operation defined in Section 5.2 of [[RFC8018]] using |prf| as the pseudo-random function, |PRF|, the password represented by {{CryptoKey/[[handle]]}} internal slot of |key| as the password, |P|, the contents of the {{Pbkdf2Params/salt}} attribute of |normalizedAlgorithm| as the salt, |S|, the value of the {{Pbkdf2Params/iterations}} attribute of |normalizedAlgorithm| as the iteration count, |c|, and |length| divided by 8 as the intended key length, |dkLen|.

  5. If the key derivation operation fails, then [= exception/throw =] an {{OperationError}}.

  6. Return |result|

Import key

  1. If |format| is not {{KeyFormat/"raw"}}, [= exception/throw =] a {{NotSupportedError}}

  2. If |usages| contains a value that is not "`deriveKey`" or "`deriveBits`", then [= exception/throw =] a {{SyntaxError}}.

  3. If |extractable| is not `false`, then [= exception/throw =] a {{SyntaxError}}.

  4. Let |key| be a new {{CryptoKey}} representing |keyData|.

  5. Set the {{CryptoKey/[[type]]}} internal slot of |key| to {{KeyType/"secret"}}.

  6. Set the {{CryptoKey/[[extractable]]}} internal slot of |key| to `false`.

  7. Let |algorithm| be a new {{KeyAlgorithm}} object.

  8. Set the {{KeyAlgorithm/name}} attribute of |algorithm| to "`PBKDF2`".

  9. Set the {{CryptoKey/[[algorithm]]}} internal slot of |key| to |algorithm|.

  10. Return |key|.

Get key length

  1. Return null.

JavaScript Example Code

Generate a signing key pair, sign some data

var encoder = new TextEncoder('utf-8');

// Algorithm Object
var algorithmKeyGen = {
  name: "RSASSA-PKCS1-v1_5",
  // RsaHashedKeyGenParams
  modulusLength: 2048,
  publicExponent: new Uint8Array([0x01, 0x00, 0x01]),  // Equivalent to 65537
  hash: {
    name: "SHA-256"
  }
};

var algorithmSign = {
  name: "RSASSA-PKCS1-v1_5"
};

window.crypto.subtle.generateKey(algorithmKeyGen, false, ["sign"]).then(
  function(key) {
    var dataPart1 = encoder.encode("hello,");
    var dataPart2 = encoder.encode(" world!");

    return window.crypto.subtle.sign(algorithmSign, key.privateKey, [dataPart1, dataPart2]);
  },
  console.error.bind(console, "Unable to generate a key")
).then(
  console.log.bind(console, "The signature is: "),
  console.error.bind(console, "Unable to sign")
);

Symmetric Encryption

var encoder = new TextEncoder('utf-8');
var clearDataArrayBufferView = encoder.encode("Plain Text Data");

var aesAlgorithmKeyGen = {
  name: "AES-CBC",
  // AesKeyGenParams
  length: 128
};

var aesAlgorithmEncrypt = {
  name: "AES-CBC",
  // AesCbcParams
  iv: window.crypto.getRandomValues(new Uint8Array(16))
};

// Create a key generator to produce a one-time-use AES key to encrypt some data
window.crypto.subtle.generateKey(aesAlgorithmKeyGen, false, ["encrypt"]).then(
  function(aesKey) {
    return window.crypto.subtle.encrypt(aesAlgorithmEncrypt, aesKey, clearDataArrayBufferView);
  }
).then(console.log.bind(console, "The ciphertext is: "),
       console.error.bind(console, "Unable to encrypt"));

Generate unique name for download

const filename = `${crypto.randomUUID()}.txt`;

IANA Considerations

JSON Web Signature and Encryption Algorithms Registration

This section registers the following algorithm identifiers in the IANA JSON Web Signature and Encryption Algorithms Registry for use with JSON Web Key. Note that the 'Implementation Requirements' field in the template refers to use with JSON Web Signature and JSON Web Encryption specifically, in which case use of unauthenticated encryption is prohibited.

  • Algorithm Name: "RS1"
  • Algorithm Description: RSASSA-PKCS1-v1_5 with SHA-1
  • Algorithm Usage Location(s): "JWK"
  • JOSE Implementation Requirements: Prohibited
  • Change Controller: W3C Web Cryptography Working Group
  • Specification Document(s): [[ This Document ]]
  • Algorithm Name: "RSA-OAEP-384"
  • Algorithm Description: RSA-OAEP using SHA-384 and MGF1 with SHA-384
  • Algorithm Usage Location(s): "alg"
  • JOSE Implementation Requirements: Optional
  • Change Controller: W3C Web Cryptography Working Group
  • Specification Document(s): [[ This Document ]]
  • Algorithm Name: "RSA-OAEP-512"
  • Algorithm Description: RSA-OAEP using SHA-512 and MGF1 with SHA-512
  • Algorithm Usage Location(s): "alg"
  • JOSE Implementation Requirements: Optional
  • Change Controller: W3C Web Cryptography Working Group
  • Specification Document(s): [[ This Document ]]
  • Algorithm Name: "A128CBC"
  • Algorithm Description: AES CBC using 128 bit key
  • Algorithm Usage Location(s): "JWK"
  • JOSE Implementation Requirements: Prohibited
  • Change Controller: W3C Web Cryptography Working Group
  • Specification Document(s): [[ This Document ]]
  • Algorithm Name: "A192CBC"
  • Algorithm Description: AES CBC using 192 bit key
  • Algorithm Usage Location(s): "JWK"
  • JOSE Implementation Requirements: Prohibited
  • Change Controller: W3C Web Cryptography Working Group
  • Specification Document(s): [[ This Document ]]
  • Algorithm Name: "A256CBC"
  • Algorithm Description: AES CBC using 256 bit key
  • Algorithm Usage Location(s): "JWK"
  • JOSE Implementation Requirements: Prohibited
  • Change Controller: W3C Web Cryptography Working Group
  • Specification Document(s): [[ This Document ]]
  • Algorithm Name: "A128CTR"
  • Algorithm Description: AES CTR using 128 bit key
  • Algorithm Usage Location(s): "JWK"
  • JOSE Implementation Requirements: Prohibited
  • Change Controller: W3C Web Cryptography Working Group
  • Specification Document(s): [[ This Document ]]
  • Algorithm Name: "A192CTR"
  • Algorithm Description: AES CTR using 192 bit key
  • Algorithm Usage Location(s): "JWK"
  • JOSE Implementation Requirements: Prohibited
  • Change Controller: W3C Web Cryptography Working Group
  • Specification Document(s): [[ This Document ]]
  • Algorithm Name: "A256CTR"
  • Algorithm Description: AES CTR using 256 bit key
  • Algorithm Usage Location(s): "JWK"
  • JOSE Implementation Requirements: Prohibited
  • Change Controller: W3C Web Cryptography Working Group
  • Specification Document(s): [[ This Document ]]
  • Algorithm Name: "HS1"
  • Algorithm Description: HMAC using SHA-1
  • Algorithm Usage Location(s): "JWK"
  • JOSE Implementation Requirements: Prohibited
  • Change Controller: W3C Web Cryptography Working Group
  • Specification Document(s): [[ This Document ]]

JSON Web Key Parameters Registration

  • Parameter Name: "ext"
  • Parameter Description: Extractable
  • Used with "kty" Value(s): *
  • Parameter Information Class: Public
  • Change Controller: W3C Web Cryptography Working Group
  • Specification Document(s): [[ This Document ]]

Acknowledgments

Thanks are due especially to Ryan Sleevi, the original author and editor, and Mark Watson, the former editor of this document.

Thanks to Adam Barth, Alex Russell, Ali Asad, Arun Ranganathan, Brian Smith, Brian Warner, Channy Yun, Charles Engelke, Eric Roman, Glenn Adams, Jim Schaad, Kai Engert, Michael Hutchinson, Michael B. Jones, Nick Van den Bleeken, Richard Barnes, Ryan Hurst, Tim Taubert, Vijay Bharadwaj, Virginie Galindo, and Wan-Teh Chang for their technical feedback and assistance.

Thanks to the W3C Web Cryptography WG, and to participants on the public-webcrypto@w3.org mailing list.

The W3C would like to thank the Northrop Grumman Cybersecurity Research Consortium for supporting W3C/MIT.

The {{Crypto/getRandomValues}} method in the {{Crypto}} interface was originally proposed by Adam Barth to the WHATWG.

Mapping between JSON Web Key / JSON Web Algorithm

Refer to algorithm-specific sections for the normative requirements of importing and exporting JWK.

Algorithm mappings

JSON Web Key AlgorithmIdentifier 
{ kty: "RSA",
  alg: "RS1" }

{ name: "RSASSA-PKCS1-v1_5",
  hash: { name: "SHA-1" }
}

{ kty: "RSA",
  alg: "RS256" }

{ name: "RSASSA-PKCS1-v1_5",
  hash: { name: "SHA-256" }
}

{ kty: "RSA",
  alg: "RS384" }

{ name: "RSASSA-PKCS1-v1_5",
  hash: { name: "SHA-384" }
}

{ kty: "RSA",
  alg: "RS512" }

{ name: "RSASSA-PKCS1-v1_5",
  hash: { name: "SHA-512" }
}

{ kty: "RSA",
  alg: "PS256" }

{ name: "RSA-PSS",
  hash: { name: "SHA-256" }
}

{ kty: "RSA",
  alg: "PS384" }

{ name: "RSA-PSS",
  hash: { name: "SHA-384" }
}

{ kty: "RSA",
  alg: "PS512" }

{ name: "RSA-PSS",
  hash: { name: "SHA-512" }
}

{ kty: "RSA",
  alg: "RSA-OAEP" }

{ name: "RSA-OAEP",
  hash: { name: "SHA-1" }
}

{ kty: "RSA",
  alg: "RSA-OAEP-256" }

{ name: "RSA-OAEP",
  hash: { name: "SHA-256" }
}

{ kty: "RSA",
  alg: "RSA-OAEP-384" }

{ name: "RSA-OAEP",
  hash: { name: "SHA-384" }
}

{ kty: "RSA",
  alg: "RSA-OAEP-512" }

{ name: "RSA-OAEP",
  hash: { name: "SHA-512" }
}

{ kty: "EC",
  alg: "ES256" }

{ name: "ECDSA",
  namedCurve: "P-256",
  hash: { name: "SHA-256" }
}

{ kty: "EC",
  alg: "ES384" }

{ name: "ECDSA",
  namedCurve: "P-384",
  hash: { name: "SHA-384" }
}

{ kty: "EC",
  alg: "ES512" }

{ name: "ECDSA",
  namedCurve: "P-521",
  hash: { name: "SHA-512" }
}

{ kty: "oct",
  alg: "A128CTR" }

{ name: "AES-CTR",
  length: 128 }

{ kty: "oct",
  alg: "A192CTR" }

{ name: "AES-CTR",
  length: 192 }

{ kty: "oct",
  alg: "A256CTR" }

{ name: "AES-CTR",
  length: 256 }

{ kty: "oct",
  alg: "A128CBC" }

{ name: "AES-CBC",
  length: 128 }

{ kty: "oct",
  alg: "A192CBC" }

{ name: "AES-CBC",
  length: 192 }

{ kty: "oct",
  alg: "A256CBC" }

{ name: "AES-CBC",
  length: 256 }

{ kty: "oct",
  alg: "A128KW" }

{ name: "AES-KW",
  length: 128 }

{ kty: "oct",
  alg: "A192KW" }

{ name: "AES-KW",
  length: 192 }

{ kty: "oct",
  alg: "A256KW" }

{ name: "AES-KW",
  length: 256 }

{ kty: "oct",
  alg: "A128GCM" }

{ name: "AES-GCM",
  length: 128 }

{ kty: "oct",
  alg: "A192GCM" }

{ name: "AES-GCM",
  length: 192 }

{ kty: "oct",
  alg: "A256GCM" }

{ name: "AES-GCM",
  length: 256 }

{ kty: "oct",
  alg: "A128GCMKW" }

{ name: "AES-GCM",
  length: 128 }

{ kty: "oct",
  alg: "A192GCMKW" }

{ name: "AES-GCM",
  length: 192 }

{ kty: "oct",
  alg: "A256GCMKW" }

{ name: "AES-GCM",
  length: 256 }

{ kty: "oct",
  alg: "HS1" }

{ name: "HMAC",
  hash: { name: "SHA-1" }
}

{ kty: "oct",
  alg: "HS256" }

{ name: "HMAC",
  hash: { name: "SHA-256" }
}

{ kty: "oct",
  alg: "HS384" }

{ name: "HMAC",
  hash: { name: "SHA-384" }
}

{ kty: "oct",
  alg: "HS512" }

{ name: "HMAC",
  hash: "SHA-512" }

Mapping between Algorithm and SubjectPublicKeyInfo

Refer to algorithm-specific sections for the normative requirements of importing and exporting SPKI.

Algorithm OID subjectPublicKey ASN.1 structure AlgorithmIdentifier Reference
rsaEncryption (1.2.840.113549.1.1.1) RSAPublicKey "`RSASSA-PKCS1-v1_5`", "`RSA-PSS`", or "`RSA-OAEP`" [[RFC3447]]
id-ecPublicKey (1.2.840.10045.2.1) ECPoint "`ECDH`" or "`ECDSA`" [[RFC5480]]

The object identifiers used by this specification do not include information about the specific algorithm and hash that the key is intended to be used with. If this is required, it's recommended that the {{KeyFormat/"jwk"}} key format is used instead.

Mapping between Algorithm and PKCS#8 PrivateKeyInfo

Refer to algorithm-specific sections for the normative requirements of importing and exporting PKCS#8 PrivateKeyInfo.

privateKeyAlgorithm privateKey format AlgorithmIdentifier Reference
rsaEncryption (1.2.840.113549.1.1.1) RSAPrivateKey "`RSASSA-PKCS1-v1_5`", "`RSA-PSS`", or "`RSA-OAEP`" [[RFC3447]]
id-ecPublicKey (1.2.840.10045.2.1) ECPrivateKey "`ECDH`" or "`ECDSA`" [[RFC5480]]