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/*
* Stream Cipher
* (C) 1999-2007 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_STREAM_CIPHER_H_
#define BOTAN_STREAM_CIPHER_H_
#include <botan/sym_algo.h>
#include <string>
#include <memory>
namespace Botan {
/**
* Base class for all stream ciphers
*/
class BOTAN_PUBLIC_API(2,0) StreamCipher : public SymmetricAlgorithm
{
public:
virtual ~StreamCipher() = default;
/**
* Create an instance based on a name
* If provider is empty then best available is chosen.
* @param algo_spec algorithm name
* @param provider provider implementation to use
* @return a null pointer if the algo/provider combination cannot be found
*/
static std::unique_ptr<StreamCipher>
create(const std::string& algo_spec,
const std::string& provider = "");
/**
* Create an instance based on a name
* If provider is empty then best available is chosen.
* @param algo_spec algorithm name
* @param provider provider implementation to use
* Throws a Lookup_Error if the algo/provider combination cannot be found
*/
static std::unique_ptr<StreamCipher>
create_or_throw(const std::string& algo_spec,
const std::string& provider = "");
/**
* @return list of available providers for this algorithm, empty if not available
*/
static std::vector<std::string> providers(const std::string& algo_spec);
/**
* Encrypt or decrypt a message
* @param in the plaintext
* @param out the byte array to hold the output, i.e. the ciphertext
* @param len the length of both in and out in bytes
*/
virtual void cipher(const uint8_t in[], uint8_t out[], size_t len) = 0;
/**
* Write keystream bytes to a buffer
* @param out the byte array to hold the keystream
* @param len the length of out in bytes
*/
virtual void write_keystream(uint8_t out[], size_t len)
{
clear_mem(out, len);
cipher1(out, len);
}
/**
* Encrypt or decrypt a message
* The message is encrypted/decrypted in place.
* @param buf the plaintext / ciphertext
* @param len the length of buf in bytes
*/
void cipher1(uint8_t buf[], size_t len)
{ cipher(buf, buf, len); }
/**
* Encrypt a message
* The message is encrypted/decrypted in place.
* @param inout the plaintext / ciphertext
*/
template<typename Alloc>
void encipher(std::vector<uint8_t, Alloc>& inout)
{ cipher(inout.data(), inout.data(), inout.size()); }
/**
* Encrypt a message
* The message is encrypted in place.
* @param inout the plaintext / ciphertext
*/
template<typename Alloc>
void encrypt(std::vector<uint8_t, Alloc>& inout)
{ cipher(inout.data(), inout.data(), inout.size()); }
/**
* Decrypt a message in place
* The message is decrypted in place.
* @param inout the plaintext / ciphertext
*/
template<typename Alloc>
void decrypt(std::vector<uint8_t, Alloc>& inout)
{ cipher(inout.data(), inout.data(), inout.size()); }
/**
* Resync the cipher using the IV
* @param iv the initialization vector
* @param iv_len the length of the IV in bytes
*/
virtual void set_iv(const uint8_t iv[], size_t iv_len) = 0;
/**
* Return the default (preferred) nonce length
* If this function returns 0, then this cipher does not support nonces
*/
virtual size_t default_iv_length() const { return 0; }
/**
* @param iv_len the length of the IV in bytes
* @return if the length is valid for this algorithm
*/
virtual bool valid_iv_length(size_t iv_len) const { return (iv_len == 0); }
/**
* @return a new object representing the same algorithm as *this
*/
virtual StreamCipher* clone() const = 0;
/**
* Set the offset and the state used later to generate the keystream
* @param offset the offset where we begin to generate the keystream
*/
virtual void seek(uint64_t offset) = 0;
/**
* @return provider information about this implementation. Default is "base",
* might also return "sse2", "avx2", "openssl", or some other arbitrary string.
*/
virtual std::string provider() const { return "base"; }
};
}
#endif
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