aes_decryptor.h

// Copyright 2016 Google LLC. 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 mbedtls.
 
#ifndef PACKAGER_MEDIA_BASE_AES_DECRYPTOR_H_
#define PACKAGER_MEDIA_BASE_AES_DECRYPTOR_H_
 
#include <cstddef>
#include <cstdint>
#include <vector>
 
#include <packager/macros/classes.h>
#include <packager/media/base/aes_cryptor.h>
#include <packager/media/base/aes_encryptor.h>
 
namespace shaka {
namespace media {
 
using AesCtrDecryptor = AesCtrEncryptor;
 
class AesCbcDecryptor : public AesCryptor {
 public:
  explicit AesCbcDecryptor(CbcPaddingScheme padding_scheme);
 
  AesCbcDecryptor(CbcPaddingScheme padding_scheme,
                  ConstantIvFlag constant_iv_flag);
 
  ~AesCbcDecryptor() override;
 
  bool InitializeWithIv(const std::vector<uint8_t>& key,
                        const std::vector<uint8_t>& iv) override;
 
  size_t RequiredOutputSize(size_t plaintext_size) override;
 
 private:
  bool CryptInternal(const uint8_t* ciphertext,
                     size_t ciphertext_size,
                     uint8_t* plaintext,
                     size_t* plaintext_size) override;
  void SetIvInternal() override;
  void CbcDecryptBlocks(const uint8_t* plaintext,
                        size_t plaintext_size,
                        uint8_t* ciphertext,
                        uint8_t* iv);
 
  const CbcPaddingScheme padding_scheme_;
  // 16-byte internal iv for crypto operations.
  std::vector<uint8_t> internal_iv_;
 
  DISALLOW_COPY_AND_ASSIGN(AesCbcDecryptor);
};
 
}  // namespace media
}  // namespace shaka
 
#endif  // PACKAGER_MEDIA_BASE_AES_DECRYPTOR_H_