shaka-packager/packager/media/base/aes_decryptor.h

61 lines
1.9 KiB
C++

// Copyright 2016 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
//
// AES Decryptor implementation using openssl.
#ifndef PACKAGER_MEDIA_BASE_AES_DECRYPTOR_H_
#define PACKAGER_MEDIA_BASE_AES_DECRYPTOR_H_
#include <vector>
#include "packager/base/macros.h"
#include "packager/media/base/aes_cryptor.h"
#include "packager/media/base/aes_encryptor.h"
namespace edash_packager {
namespace media {
/// For AES-CTR, encryption and decryption are identical.
using AesCtrDecryptor = AesCtrEncryptor;
/// Class which implements AES-CBC (Cipher block chaining) decryption.
class AesCbcDecryptor : public AesCryptor {
public:
/// @param padding_scheme indicates the padding scheme used. Currently
/// supported schemes: kNoPadding, kPkcs5Padding, kCtsPadding.
/// @param chain_across_calls indicates whether there is a continuous cipher
/// block chain across calls for Decrypt function. If it is false, iv
/// is not updated across Decrypt function calls.
AesCbcDecryptor(CbcPaddingScheme padding_scheme, bool chain_across_calls);
~AesCbcDecryptor() override;
/// @name AesCryptor implementation overrides.
/// @{
bool InitializeWithIv(const std::vector<uint8_t>& key,
const std::vector<uint8_t>& iv) override;
bool SetIv(const std::vector<uint8_t>& iv) override;
void UpdateIv() override {
// Nop for decryptor.
}
/// @}
private:
bool CryptInternal(const uint8_t* ciphertext,
size_t ciphertext_size,
uint8_t* plaintext,
size_t* plaintext_size) override;
const CbcPaddingScheme padding_scheme_;
const bool chain_across_calls_;
DISALLOW_COPY_AND_ASSIGN(AesCbcDecryptor);
};
} // namespace media
} // namespace edash_packager
#endif // PACKAGER_MEDIA_BASE_AES_DECRYPTOR_H_