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/*
* Cipher Modes
* (C) 2015 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/cipher_mode.h>
#include <botan/lookup.h>
#include <sstream>
namespace Botan {
Cipher_Mode* get_cipher_mode(const std::string& algo_spec, Cipher_Dir direction)
{
const std::string provider = "";
const char* dir_string = (direction == ENCRYPTION) ? "_Encryption" : "_Decryption";
std::unique_ptr<Transform> t;
t.reset(get_transform(algo_spec, provider, dir_string));
if(Cipher_Mode* cipher = dynamic_cast<Cipher_Mode*>(t.get()))
{
t.release();
return cipher;
}
const std::vector<std::string> algo_parts = split_on(algo_spec, '/');
if(algo_parts.size() < 2)
return nullptr;
const std::string cipher_name = algo_parts[0];
const std::vector<std::string> mode_info = parse_algorithm_name(algo_parts[1]);
if(mode_info.empty())
return nullptr;
std::ostringstream alg_args;
alg_args << '(' << cipher_name;
for(size_t i = 1; i < mode_info.size(); ++i)
alg_args << ',' << mode_info[i];
for(size_t i = 2; i < algo_parts.size(); ++i)
alg_args << ',' << algo_parts[i];
alg_args << ')';
const std::string mode_name = mode_info[0] + alg_args.str();
const std::string mode_name_directional = mode_info[0] + dir_string + alg_args.str();
t.reset(get_transform(mode_name_directional, provider));
if(Cipher_Mode* cipher = dynamic_cast<Cipher_Mode*>(t.get()))
{
t.release();
return cipher;
}
t.reset(get_transform(mode_name, provider));
if(Cipher_Mode* cipher = dynamic_cast<Cipher_Mode*>(t.get()))
{
t.release();
return cipher;
}
if(StreamCipher* stream_cipher = get_stream_cipher(mode_name, provider))
return new Stream_Cipher_Mode(stream_cipher);
return nullptr;
}
}
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