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/*
* XTS mode, from IEEE P1619
* (C) 2009,2013 Jack Lloyd
* (C) 2016 Daniel Neus, Rohde & Schwarz Cybersecurity
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_MODE_XTS_H_
#define BOTAN_MODE_XTS_H_
#include <botan/cipher_mode.h>
#include <botan/block_cipher.h>
BOTAN_FUTURE_INTERNAL_HEADER(xts.h)
namespace Botan {
/**
* IEEE P1619 XTS Mode
*/
class BOTAN_PUBLIC_API(2,0) XTS_Mode : public Cipher_Mode
{
public:
std::string name() const override;
size_t update_granularity() const override { return m_cipher_parallelism; }
size_t minimum_final_size() 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:
explicit XTS_Mode(BlockCipher* cipher);
const uint8_t* tweak() const { return m_tweak.data(); }
bool tweak_set() const { return m_tweak.empty() == false; }
const BlockCipher& cipher() const { return *m_cipher; }
void update_tweak(size_t last_used);
size_t cipher_block_size() const { return m_cipher_block_size; }
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<BlockCipher> m_tweak_cipher;
secure_vector<uint8_t> m_tweak;
const size_t m_cipher_block_size;
const size_t m_cipher_parallelism;
};
/**
* IEEE P1619 XTS Encryption
*/
class BOTAN_PUBLIC_API(2,0) XTS_Encryption final : public XTS_Mode
{
public:
/**
* @param cipher underlying block cipher
*/
explicit XTS_Encryption(BlockCipher* cipher) : XTS_Mode(cipher) {}
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;
};
/**
* IEEE P1619 XTS Decryption
*/
class BOTAN_PUBLIC_API(2,0) XTS_Decryption final : public XTS_Mode
{
public:
/**
* @param cipher underlying block cipher
*/
explicit XTS_Decryption(BlockCipher* cipher) : XTS_Mode(cipher) {}
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;
};
}
#endif