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// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_CDM_AES_CBC_CRYPTO_H_
#define MEDIA_CDM_AES_CBC_CRYPTO_H_
#include <stdint.h>
#include <string>
#include "base/containers/span.h"
#include "base/macros.h"
#include "media/base/media_export.h"
#include "third_party/boringssl/src/include/openssl/evp.h"
namespace crypto {
class SymmetricKey;
}
namespace media {
// This class implements AES-CBC-128 decryption as described in the Advanced
// Encryption Standard specified by AES [FIPS-197, https://www.nist.gov]
// using 128-bit keys in Cipher Block Chaining mode, as specified in Block
// Cipher Modes [NIST 800-38A, https://www.nist.gov].
class MEDIA_EXPORT AesCbcCrypto {
public:
AesCbcCrypto();
~AesCbcCrypto();
// Initializes the encryptor using |key| and |iv|. Returns false if either
// the key or the initialization vector cannot be used.
bool Initialize(const crypto::SymmetricKey& key,
base::span<const uint8_t> iv);
// Decrypts |encrypted_data| into |decrypted_data|. |encrypted_data| must be
// a multiple of the blocksize (128 bits), and |decrypted_data| must have
// enough space for |encrypted_data|.size(). Returns false if the decryption
// fails.
bool Decrypt(base::span<const uint8_t> encrypted_data,
uint8_t* decrypted_data);
private:
EVP_CIPHER_CTX ctx_;
DISALLOW_COPY_AND_ASSIGN(AesCbcCrypto);
};
} // namespace media
#endif // MEDIA_CDM_AES_CBC_CRYPTO_H_