fizz::X25519KeyExchange Class Reference

#include <X25519.h>

Inheritance diagram for fizz::X25519KeyExchange:

Public Member Functions
	~X25519KeyExchange () override=default
void	generateKeyPair () override
std::unique_ptr< folly::IOBuf >	getKeyShare () const override
std::unique_ptr< folly::IOBuf >	generateSharedSecret (folly::ByteRange keyShare) const override
Public Member Functions inherited from fizz::KeyExchange
virtual	~KeyExchange ()=default

Private Types
using	PrivKey = std::array< uint8_t, crypto_scalarmult_SCALARBYTES >
using	PubKey = std::array< uint8_t, crypto_scalarmult_BYTES >

Private Attributes
folly::Optional< PrivKey >	privKey_
folly::Optional< PubKey >	pubKey_

Detailed Description

X25519 key exchange implementation using libsodium.

Definition at line 23 of file X25519.h.

Member Typedef Documentation

using fizz::X25519KeyExchange::PrivKey = std::array<uint8_t, crypto_scalarmult_SCALARBYTES>

private

Definition at line 32 of file X25519.h.

using fizz::X25519KeyExchange::PubKey = std::array<uint8_t, crypto_scalarmult_BYTES>

private

Definition at line 33 of file X25519.h.

Constructor & Destructor Documentation

fizz::X25519KeyExchange::~X25519KeyExchange ( )

overridedefault

Member Function Documentation

void fizz::X25519KeyExchange::generateKeyPair ( )

overridevirtual

Generates an ephemeral key pair.

Implements fizz::KeyExchange.

Definition at line 20 of file X25519.cpp.

References folly::gen::move.

Referenced by fizz::test::TEST().

                                        {
  auto privKey = PrivKey();
  auto pubKey = PubKey();
  auto err = crypto_box_curve25519xsalsa20poly1305_keypair(
      pubKey.data(), privKey.data());
  if (err != 0) {
    throw std::runtime_error(to<std::string>("Could not generate keys ", err));
  }
  privKey_ = std::move(privKey);
  pubKey_ = std::move(pubKey);
}

std::unique_ptr< folly::IOBuf > fizz::X25519KeyExchange::generateSharedSecret ( folly::ByteRange  keyShare ) const

overridevirtual

Generate a shared secret with our key pair and a peer's public key share.

Performs all necessary validation of the public key share and throws on error.

generateKeyPair() must be called before.

Implements fizz::KeyExchange.

Definition at line 39 of file X25519.cpp.

References folly::IOBuf::create(), folly::Range< Iter >::data(), and folly::Range< Iter >::size().

Referenced by fizz::test::TEST().

                                   {
  if (!privKey_ || !pubKey_) {
    throw std::runtime_error("Key not generated");
  }
  if (keyShare.size() != crypto_scalarmult_BYTES) {
    throw std::runtime_error("Invalid external public key");
  }
  auto key = IOBuf::create(crypto_scalarmult_BYTES);
  key->append(crypto_scalarmult_BYTES);
  int err =
      crypto_scalarmult(key->writableData(), privKey_->data(), keyShare.data());
  if (err != 0) {
    throw std::runtime_error("Invalid point");
  }
  return key;
}

std::unique_ptr< IOBuf > fizz::X25519KeyExchange::getKeyShare ( ) const

overridevirtual

Returns the public key to share with peers.

generateKeyPair() must be called before.

Implements fizz::KeyExchange.

Definition at line 32 of file X25519.cpp.

References folly::IOBuf::copyBuffer().

                                                          {
  if (!privKey_ || !pubKey_) {
    throw std::runtime_error("Key not generated");
  }
  return IOBuf::copyBuffer(pubKey_->data(), pubKey_->size());
}

Member Data Documentation

folly::Optional<PrivKey> fizz::X25519KeyExchange::privKey_

private

Definition at line 35 of file X25519.h.

folly::Optional<PubKey> fizz::X25519KeyExchange::pubKey_

private

Definition at line 36 of file X25519.h.

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The documentation for this class was generated from the following files:

• proxygen/fizz/fizz/crypto/exchange/X25519.h
• proxygen/fizz/fizz/crypto/exchange/X25519.cpp