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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_DLL CTR_BE final : public StreamCipher
{
public:
void cipher(const byte in[], byte out[], size_t length) override;
void set_iv(const byte iv[], size_t iv_len) override;
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()); }
void clear() override;
static CTR_BE* make(const Spec& spec);
/**
* @param cipher the block cipher to use
*/
explicit CTR_BE(BlockCipher* cipher);
CTR_BE(BlockCipher* cipher, size_t ctr_size);
void seek(u64bit offset) override;
private:
void key_schedule(const byte key[], size_t key_len) override;
void increment_counter();
std::unique_ptr<BlockCipher> m_cipher;
secure_vector<byte> m_counter, m_pad;
size_t m_ctr_size;
size_t m_pad_pos;
};
}
#endif
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