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/*
* CBC mode
* (C) 1999-2007,2013 Jack Lloyd
* (C) 2016 Daniel Neus, Rohde & Schwarz Cybersecurity
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_MODE_CBC_H_
#define BOTAN_MODE_CBC_H_
#include <botan/cipher_mode.h>
#include <botan/block_cipher.h>
#include <botan/mode_pad.h>
namespace Botan {
/**
* CBC Mode
*/
class BOTAN_PUBLIC_API(2,0) CBC_Mode : public Cipher_Mode
{
public:
std::string name() const override;
size_t update_granularity() const override;
Key_Length_Specification key_spec() const override;
size_t default_nonce_length() const override;
bool valid_nonce_length(size_t n) const override;
void clear() override;
void reset() override;
protected:
CBC_Mode(BlockCipher* cipher, BlockCipherModePaddingMethod* padding);
const BlockCipher& cipher() const { return *m_cipher; }
const BlockCipherModePaddingMethod& padding() const
{
BOTAN_ASSERT_NONNULL(m_padding);
return *m_padding;
}
size_t block_size() const { return m_block_size; }
secure_vector<uint8_t>& state() { return m_state; }
uint8_t* state_ptr() { return m_state.data(); }
private:
void start_msg(const uint8_t nonce[], size_t nonce_len) override;
void key_schedule(const uint8_t key[], size_t length) override;
std::unique_ptr<BlockCipher> m_cipher;
std::unique_ptr<BlockCipherModePaddingMethod> m_padding;
secure_vector<uint8_t> m_state;
size_t m_block_size;
};
/**
* CBC Encryption
*/
class BOTAN_PUBLIC_API(2,0) CBC_Encryption : public CBC_Mode
{
public:
/**
* @param cipher block cipher to use
* @param padding padding method to use
*/
CBC_Encryption(BlockCipher* cipher, BlockCipherModePaddingMethod* padding) :
CBC_Mode(cipher, padding) {}
size_t process(uint8_t buf[], size_t size) override;
void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
size_t output_length(size_t input_length) const override;
size_t minimum_final_size() const override;
};
/**
* CBC Encryption with ciphertext stealing (CBC-CS3 variant)
*/
class BOTAN_PUBLIC_API(2,0) CTS_Encryption final : public CBC_Encryption
{
public:
/**
* @param cipher block cipher to use
*/
explicit CTS_Encryption(BlockCipher* cipher) : CBC_Encryption(cipher, nullptr) {}
size_t output_length(size_t input_length) const override;
void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
size_t minimum_final_size() const override;
bool valid_nonce_length(size_t n) const override;
};
/**
* CBC Decryption
*/
class BOTAN_PUBLIC_API(2,0) CBC_Decryption : public CBC_Mode
{
public:
/**
* @param cipher block cipher to use
* @param padding padding method to use
*/
CBC_Decryption(BlockCipher* cipher, BlockCipherModePaddingMethod* padding) :
CBC_Mode(cipher, padding), m_tempbuf(update_granularity()) {}
size_t process(uint8_t buf[], size_t size) override;
void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
size_t output_length(size_t input_length) const override;
size_t minimum_final_size() const override;
void reset() override;
private:
secure_vector<uint8_t> m_tempbuf;
};
/**
* CBC Decryption with ciphertext stealing (CBC-CS3 variant)
*/
class BOTAN_PUBLIC_API(2,0) CTS_Decryption final : public CBC_Decryption
{
public:
/**
* @param cipher block cipher to use
*/
explicit CTS_Decryption(BlockCipher* cipher) : CBC_Decryption(cipher, nullptr) {}
void finish(secure_vector<uint8_t>& final_block, size_t offset = 0) override;
size_t minimum_final_size() const override;
bool valid_nonce_length(size_t n) const override;
};
}
#endif
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