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/*
* Cipher Modes
* (C) 2013 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_CIPHER_MODE_H__
#define BOTAN_CIPHER_MODE_H__
#include <botan/transform.h>
#include <botan/stream_cipher.h>
namespace Botan {
/**
* Interface for cipher modes
*/
class BOTAN_DLL Cipher_Mode : public Keyed_Transform
{
public:
/**
* Returns true iff this mode provides authentication as well as
* confidentiality.
*/
virtual bool authenticated() const { return false; }
};
class BOTAN_DLL Stream_Cipher_Mode : public Cipher_Mode
{
public:
Stream_Cipher_Mode(StreamCipher* cipher) : m_cipher(cipher) {}
void update(secure_vector<byte>& buf, size_t offset) override
{
if(offset < buf.size())
m_cipher->cipher1(&buf[offset], buf.size() - offset);
}
void finish(secure_vector<byte>& buf, size_t offset) override
{ return update(buf, offset); }
size_t output_length(size_t input_length) const override { return input_length; }
size_t update_granularity() const override { return 64; /* arbitrary */ }
size_t minimum_final_size() const override { return 0; }
size_t default_nonce_length() const override { return 0; }
bool valid_nonce_length(size_t nonce_len) const override
{ return m_cipher->valid_iv_length(nonce_len); }
Key_Length_Specification key_spec() const override { return m_cipher->key_spec(); }
std::string name() const override { return m_cipher->name(); }
void clear() override { return m_cipher->clear(); }
private:
secure_vector<byte> start_raw(const byte nonce[], size_t nonce_len) override
{
m_cipher->set_iv(nonce, nonce_len);
return secure_vector<byte>();
}
void key_schedule(const byte key[], size_t length)
{
m_cipher->set_key(key, length);
}
std::unique_ptr<StreamCipher> m_cipher;
};
BOTAN_DLL Cipher_Mode* get_cipher_mode(const std::string& algo_spec, Cipher_Dir direction);
}
#endif
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