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/*
* CTR-BE Mode
* (C) 1999-2007 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_CTR_BE_H_
#define BOTAN_CTR_BE_H_
#include <botan/block_cipher.h>
#include <botan/stream_cipher.h>
namespace Botan {
/**
* CTR-BE (Counter mode, big-endian)
*/
class BOTAN_PUBLIC_API(2,0) CTR_BE final : public StreamCipher
{
public:
void cipher(const uint8_t in[], uint8_t out[], size_t length) override;
void set_iv(const uint8_t iv[], size_t iv_len) override;
size_t default_iv_length() const override { return m_cipher->block_size(); }
bool valid_iv_length(size_t iv_len) const override
{ return (iv_len <= m_cipher->block_size()); }
Key_Length_Specification key_spec() const override
{
return m_cipher->key_spec();
}
std::string name() const override;
CTR_BE* clone() const override
{ return new CTR_BE(m_cipher->clone(), m_ctr_size); }
void clear() override;
/**
* @param cipher the block cipher to use
*/
explicit CTR_BE(BlockCipher* cipher);
CTR_BE(BlockCipher* cipher, size_t ctr_size);
void seek(uint64_t offset) override;
private:
void key_schedule(const uint8_t key[], size_t key_len) override;
void add_counter(const uint64_t counter);
std::unique_ptr<BlockCipher> m_cipher;
const size_t m_block_size;
const size_t m_ctr_size;
const size_t m_ctr_blocks;
secure_vector<uint8_t> m_counter, m_pad;
std::vector<uint8_t> m_iv;
size_t m_pad_pos;
};
}
#endif
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