shaka-packager/media/base/aes_encryptor.h

265 lines
9.0 KiB
C++

// Copyright 2014 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 Encryptor implementation using openssl.
#ifndef MEDIA_BASE_AES_ENCRYPTOR_H_
#define MEDIA_BASE_AES_ENCRYPTOR_H_
#include <string>
#include <vector>
#include "base/memory/scoped_ptr.h"
#include "base/stl_util.h"
struct aes_key_st;
typedef struct aes_key_st AES_KEY;
namespace edash_packager {
namespace media {
// Class which implements AES-CTR counter-mode encryption/decryption.
class AesCtrEncryptor {
public:
AesCtrEncryptor();
~AesCtrEncryptor();
/// Initialize the encryptor with specified key and a random generated IV
/// of the specified size. block_offset() is reset to 0 on success.
/// @param key should be 16 bytes in size as specified in CENC spec.
/// @param iv_size should be either 8 or 16 as specified in CENC spec.
/// @return true on successful initialization, false otherwise.
bool InitializeWithRandomIv(const std::vector<uint8>& key, uint8 iv_size);
/// Initialize the encryptor with specified key and IV. block_offset() is
/// reset to 0 on success.
/// @param key should be 16 bytes in size as specified in CENC spec.
/// @param iv should be 8 bytes or 16 bytes in size as specified in CENC spec.
/// @return true on successful initialization, false otherwise.
bool InitializeWithIv(const std::vector<uint8>& key,
const std::vector<uint8>& iv);
/// @name Various forms of encrypt calls.
/// block_offset() will be updated according to input plaintext size.
/// @{
bool Encrypt(const uint8* plaintext,
size_t plaintext_size,
uint8* ciphertext);
bool Encrypt(const std::vector<uint8>& plaintext,
std::vector<uint8>* ciphertext) {
ciphertext->resize(plaintext.size());
return Encrypt(&plaintext[0], plaintext.size(), &(*ciphertext)[0]);
}
bool Encrypt(const std::string& plaintext, std::string* ciphertext) {
ciphertext->resize(plaintext.size());
return Encrypt(reinterpret_cast<const uint8*>(plaintext.data()),
plaintext.size(),
reinterpret_cast<uint8*>(string_as_array(ciphertext)));
}
/// @}
// For AES CTR, encryption and decryption are identical.
bool Decrypt(const uint8* ciphertext,
size_t ciphertext_size,
uint8* plaintext) {
return Encrypt(ciphertext, ciphertext_size, plaintext);
}
bool Decrypt(const std::vector<uint8>& ciphertext,
std::vector<uint8>* plaintext) {
return Encrypt(ciphertext, plaintext);
}
bool Decrypt(const std::string& ciphertext, std::string* plaintext) {
return Encrypt(ciphertext, plaintext);
}
/// Update IV for next sample. @a block_offset_ is reset to 0.
/// As recommended in ISO/IEC FDIS 23001-7: CENC spec,
/// For 64-bit IV size, new_iv = old_iv + 1;
/// For 128-bit IV size, new_iv = old_iv + previous_sample_block_count.
void UpdateIv();
/// Set IV. @a block_offset_ is reset to 0 on success.
/// @return true if successful, false if the input is invalid.
bool SetIv(const std::vector<uint8>& iv);
const std::vector<uint8>& iv() const { return iv_; }
uint32 block_offset() const { return block_offset_; }
private:
// Initialization vector, with size 8 or 16.
std::vector<uint8> iv_;
// Current block offset.
uint32 block_offset_;
// Openssl AES_KEY.
scoped_ptr<AES_KEY> aes_key_;
// Current AES-CTR counter.
std::vector<uint8> counter_;
// Encrypted counter.
std::vector<uint8> encrypted_counter_;
// Keep track of whether the counter has overflowed.
bool counter_overflow_;
DISALLOW_COPY_AND_ASSIGN(AesCtrEncryptor);
};
// Class which implements AES-CBC (Cipher block chaining) encryption with
// PKCS#5 padding.
class AesCbcPkcs5Encryptor {
public:
AesCbcPkcs5Encryptor();
~AesCbcPkcs5Encryptor();
/// Initialize the encryptor with specified key and IV.
/// @param key should be 128 bits or 192 bits or 256 bits in size as defined
/// in AES spec.
/// @param iv should be 16 bytes in size.
/// @return true on successful initialization, false otherwise.
bool InitializeWithIv(const std::vector<uint8>& key,
const std::vector<uint8>& iv);
/// @param plaintext will be PKCS5 padded before being encrypted.
/// @param ciphertext should not be NULL.
void Encrypt(const std::string& plaintext, std::string* ciphertext);
/// @return true if successful, false if the input is invalid.
bool SetIv(const std::vector<uint8>& iv);
const std::vector<uint8>& iv() const { return iv_; }
private:
std::vector<uint8> iv_;
scoped_ptr<AES_KEY> encrypt_key_;
DISALLOW_COPY_AND_ASSIGN(AesCbcPkcs5Encryptor);
};
// Class which implements AES-CBC (Cipher block chaining) decryption with
// PKCS#5 padding.
class AesCbcPkcs5Decryptor {
public:
AesCbcPkcs5Decryptor();
~AesCbcPkcs5Decryptor();
/// Initialize the decryptor with specified key and IV.
/// @param key should be 128 bits or 192 bits or 256 bits in size as defined
/// in AES spec.
/// @param iv should be 16 bytes in size.
/// @return true on successful initialization, false otherwise.
bool InitializeWithIv(const std::vector<uint8>& key,
const std::vector<uint8>& iv);
/// @param ciphertext is expected to be padded with PKCS5 padding.
/// @param plaintext should not be NULL.
/// @return true on success, false otherwise.
bool Decrypt(const std::string& ciphertext, std::string* plaintext);
/// @return true if successful, false if the input is invalid.
bool SetIv(const std::vector<uint8>& iv);
const std::vector<uint8>& iv() const { return iv_; }
private:
std::vector<uint8> iv_;
scoped_ptr<AES_KEY> decrypt_key_;
DISALLOW_COPY_AND_ASSIGN(AesCbcPkcs5Decryptor);
};
// Class which implements AES-CBC (Cipher block chaining) encryption with
// Ciphertext stealing.
class AesCbcCtsEncryptor {
public:
AesCbcCtsEncryptor();
~AesCbcCtsEncryptor();
/// Initialize the encryptor with specified key and IV.
/// @param key should be 128 bits or 192 bits or 256 bits in size as defined
/// in AES spec.
/// @param iv should be 16 bytes in size.
/// @return true on successful initialization, false otherwise.
bool InitializeWithIv(const std::vector<uint8>& key,
const std::vector<uint8>& iv);
/// @param plaintext points to the data to be encrypted.
/// @param size is the number of bytes to be encrypted. If less than 16
/// bytes, it will be copied in the clear.
/// @param ciphertext should not be NULL. The buffer should be at least
/// @a size bytes in length.
void Encrypt(const uint8* plaintext,
size_t size,
uint8* ciphertext);
/// @param plaintext contains the data to be encrypted. If less than 16
/// bytes in size, it will be copied in the clear.
/// @param ciphertext should not be NULL. Caller retains ownership.
void Encrypt(const std::vector<uint8>& plaintext,
std::vector<uint8>* ciphertext);
/// @param iv is the initialization vector. Should be 16 bytes in size.
/// @return true if successful, false if the input is invalid.
bool SetIv(const std::vector<uint8>& iv);
const std::vector<uint8>& iv() const { return iv_; }
private:
std::vector<uint8> iv_;
scoped_ptr<AES_KEY> encrypt_key_;
DISALLOW_COPY_AND_ASSIGN(AesCbcCtsEncryptor);
};
// Class which implements AES-CBC (Cipher block chaining) decryption with
// Ciphertext stealing.
class AesCbcCtsDecryptor {
public:
AesCbcCtsDecryptor();
~AesCbcCtsDecryptor();
/// Initialize the decryptor with specified key and IV.
/// @param key should be 128 bits or 192 bits or 256 bits in size as defined
/// in AES spec.
/// @param iv should be 16 bytes in size.
/// @return true on successful initialization, false otherwise.
bool InitializeWithIv(const std::vector<uint8>& key,
const std::vector<uint8>& iv);
/// @param ciphertext points to the data to be decrypted.
/// @param size is the number of bytes to be decrypted. If less than 16
/// bytes, it will be copied in the clear.
/// @param plaintext should not be NULL. The buffer should be at least
/// @a size bytes in length.
void Decrypt(const uint8* ciphertext,
size_t size,
uint8* plaintext);
/// @param ciphertext contains the data to be decrypted. If less than 16
/// bytes in size, it will be copied in the clear.
/// @param plaintext should not be NULL. Caller retains ownership.
void Decrypt(const std::vector<uint8>& ciphertext,
std::vector<uint8>* plaintext);
/// @return true if successful, false if the input is invalid.
bool SetIv(const std::vector<uint8>& iv);
const std::vector<uint8>& iv() const { return iv_; }
private:
std::vector<uint8> iv_;
scoped_ptr<AES_KEY> decrypt_key_;
DISALLOW_COPY_AND_ASSIGN(AesCbcCtsDecryptor);
};
} // namespace media
} // namespace edash_packager
#endif // MEDIA_BASE_AES_ENCRYPTOR_H_