Hkdf.h

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/*
 *  Copyright (c) 2018-present, Facebook, Inc.
 *  All rights reserved.
 *
 *  This source code is licensed under the BSD-style license found in the
 *  LICENSE file in the root directory of this source tree.
 */

#pragma once

#include <fizz/crypto/Sha256.h>
#include <fizz/crypto/Sha384.h>
#include <folly/io/IOBuf.h>

namespace fizz {
class Hkdf {
 public:
  virtual ~Hkdf() = default;

  virtual std::vector<uint8_t> extract(
      folly::ByteRange salt,
      folly::ByteRange ikm) const = 0;

  virtual std::unique_ptr<folly::IOBuf> expand(
      folly::ByteRange extractedKey,
      const folly::IOBuf& info,
      size_t outputBytes) const = 0;

  virtual std::unique_ptr<folly::IOBuf> hkdf(
      folly::ByteRange ikm,
      folly::ByteRange salt,
      const folly::IOBuf& info,
      size_t outputBytes) const = 0;

  virtual size_t hashLength() const = 0;
};

template <typename Hash>
class HkdfImpl : public Hkdf {
 public:
  static constexpr size_t HashLen = Hash::HashLen;

  std::vector<uint8_t> extract(folly::ByteRange salt, folly::ByteRange ikm)
      const override;

  std::unique_ptr<folly::IOBuf> expand(
      folly::ByteRange extractedKey,
      const folly::IOBuf& info,
      size_t outputBytes) const override;

  std::unique_ptr<folly::IOBuf> hkdf(
      folly::ByteRange ikm,
      folly::ByteRange salt,
      const folly::IOBuf& info,
      size_t outputBytes) const override;

  size_t hashLength() const override {
    return HashLen;
  }
};
} // namespace fizz

#include <fizz/crypto/Hkdf-inl.h>