blob: f35e7ff990312f596ba7f7ad94c08b185fbc7e97 [file] [log] [blame]
* Copyright 2018 The WebRTC Project Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
#include <stddef.h>
#include <stdint.h>
#include <memory>
#include "absl/types/optional.h"
#include "api/array_view.h"
#include "rtc_base/buffer.h"
#include "rtc_base/constructor_magic.h"
namespace rtc {
// Defines the set of key derivation algorithms that are supported. It is ideal
// to keep this list as small as possible.
enum class KeyDerivationAlgorithm {
// This algorithm is not suitable to generate a key from a password. Please
// only use with a cryptographically random master secret.
// KeyDerivation provides a generic interface for deriving keys in WebRTC. This
// class should be used over directly accessing openssl or boringssl primitives
// so that we can maintain seperate implementations.
// Example:
// auto kd = KeyDerivation::Create(KeyDerivationAlgorithm::HDKF_SHA526);
// if (kd == nullptr) return;
// auto derived_key_or = kd->DeriveKey(secret, salt, label);
// if (!derived_key_or.ok()) return;
// DoSomethingWithKey(derived_key_or.value());
class KeyDerivation {
virtual ~KeyDerivation();
// Derives a new key from existing key material.
// secret - The random secret value you wish to derive a key from.
// salt - Optional but recommended (non secret) cryptographically random.
// label - A non secret but unique label value to determine the derivation.
// derived_key_byte_size - This must be at least 128 bits.
// return - An optional ZeroOnFreeBuffer containing the derived key or
// absl::nullopt. Nullopt indicates a failure in derivation.
virtual absl::optional<ZeroOnFreeBuffer<uint8_t>> DeriveKey(
rtc::ArrayView<const uint8_t> secret,
rtc::ArrayView<const uint8_t> salt,
rtc::ArrayView<const uint8_t> label,
size_t derived_key_byte_size) = 0;
// Static factory that will return an implementation that is capable of
// handling the key derivation with the requested algorithm. If no
// implementation is available nullptr will be returned.
static std::unique_ptr<KeyDerivation> Create(
KeyDerivationAlgorithm key_derivation_algorithm);
} // namespace rtc