72 lines
2.5 KiB
C++
72 lines
2.5 KiB
C++
// Copyright 2016 Google LLC. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file or at
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// https://developers.google.com/open-source/licenses/bsd
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//
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// AES Decryptor implementation using mbedtls.
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#ifndef PACKAGER_MEDIA_BASE_AES_DECRYPTOR_H_
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#define PACKAGER_MEDIA_BASE_AES_DECRYPTOR_H_
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#include <vector>
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#include "packager/macros.h"
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#include "packager/media/base/aes_cryptor.h"
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#include "packager/media/base/aes_encryptor.h"
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namespace shaka {
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namespace media {
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/// For AES-CTR, encryption and decryption are identical.
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using AesCtrDecryptor = AesCtrEncryptor;
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/// Class which implements AES-CBC (Cipher block chaining) decryption.
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class AesCbcDecryptor : public AesCryptor {
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public:
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/// Creates a AesCbcDecryptor with continous cipher block chain across Crypt
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/// calls.
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/// @param padding_scheme indicates the padding scheme used. Currently
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/// supported schemes: kNoPadding, kPkcs5Padding, kCtsPadding.
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explicit AesCbcDecryptor(CbcPaddingScheme padding_scheme);
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/// @param padding_scheme indicates the padding scheme used. Currently
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/// supported schemes: kNoPadding, kPkcs5Padding, kCtsPadding.
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/// @param constant_iv_flag indicates whether a constant iv is used,
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/// kUseConstantIv means that the same iv is used for all Crypt calls
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/// until iv is changed via SetIv; otherwise, iv is updated internally
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/// and there is a continuous cipher block chain across Crypt calls
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/// util iv is changed explicitly via SetIv or UpdateIv functions.
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AesCbcDecryptor(CbcPaddingScheme padding_scheme,
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ConstantIvFlag constant_iv_flag);
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~AesCbcDecryptor() override;
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/// @name AesCryptor implementation overrides.
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/// @{
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bool InitializeWithIv(const std::vector<uint8_t>& key,
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const std::vector<uint8_t>& iv) override;
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/// @}
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private:
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bool CryptInternal(const uint8_t* ciphertext,
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size_t ciphertext_size,
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uint8_t* plaintext,
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size_t* plaintext_size) override;
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void SetIvInternal() override;
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void CbcDecryptBlocks(const uint8_t* plaintext,
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size_t plaintext_size,
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uint8_t* ciphertext);
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const CbcPaddingScheme padding_scheme_;
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// 16-byte internal iv for crypto operations.
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std::vector<uint8_t> internal_iv_;
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DISALLOW_COPY_AND_ASSIGN(AesCbcDecryptor);
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};
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} // namespace media
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} // namespace shaka
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#endif // PACKAGER_MEDIA_BASE_AES_DECRYPTOR_H_
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