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/*
* Algorithm Retrieval
* (C) 1999-2007 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/lookup.h>
#include <botan/cipher_mode.h>
#include <botan/filters.h>
#include <botan/libstate.h>
#include <botan/parsing.h>
#include <botan/transform_filter.h>
#if defined(BOTAN_HAS_OFB)
#include <botan/ofb.h>
#endif
#if defined(BOTAN_HAS_CTR_BE)
#include <botan/ctr.h>
#endif
namespace Botan {
/*
* Get a PBKDF algorithm by name
*/
PBKDF* get_pbkdf(const std::string& algo_spec)
{
Algorithm_Factory& af = global_state().algorithm_factory();
if(PBKDF* pbkdf = af.make_pbkdf(algo_spec))
return pbkdf;
throw Algorithm_Not_Found(algo_spec);
}
/*
* Query if an algorithm exists
*/
bool have_algorithm(const std::string& name)
{
Algorithm_Factory& af = global_state().algorithm_factory();
if(af.prototype_block_cipher(name))
return true;
if(af.prototype_stream_cipher(name))
return true;
if(af.prototype_hash_function(name))
return true;
if(af.prototype_mac(name))
return true;
return false;
}
/*
* Query the block size of a cipher or hash
*/
size_t block_size_of(const std::string& name)
{
Algorithm_Factory& af = global_state().algorithm_factory();
if(const BlockCipher* cipher = af.prototype_block_cipher(name))
return cipher->block_size();
if(const HashFunction* hash = af.prototype_hash_function(name))
return hash->hash_block_size();
throw Algorithm_Not_Found(name);
}
/*
* Query the output_length() of a hash or MAC
*/
size_t output_length_of(const std::string& name)
{
Algorithm_Factory& af = global_state().algorithm_factory();
if(const HashFunction* hash = af.prototype_hash_function(name))
return hash->output_length();
if(const MessageAuthenticationCode* mac = af.prototype_mac(name))
return mac->output_length();
throw Algorithm_Not_Found(name);
}
/*
* Get a cipher object
*/
Keyed_Filter* get_cipher(const std::string& algo_spec,
Cipher_Dir direction)
{
Algorithm_Factory& af = global_state().algorithm_factory();
std::unique_ptr<Cipher_Mode> c(get_cipher_mode(algo_spec, direction));
if(c)
return new Transform_Filter(c.release());
std::vector<std::string> algo_parts = split_on(algo_spec, '/');
if(algo_parts.empty())
throw Invalid_Algorithm_Name(algo_spec);
const std::string cipher_name = algo_parts[0];
// check if it is a stream cipher first (easy case)
const StreamCipher* stream_cipher = af.prototype_stream_cipher(cipher_name);
if(stream_cipher)
return new StreamCipher_Filter(stream_cipher->clone());
const BlockCipher* block_cipher = af.prototype_block_cipher(cipher_name);
if(!block_cipher)
return nullptr;
if(algo_parts.size() >= 4)
return nullptr; // 4 part mode, not something we know about
if(algo_parts.size() < 2)
throw Lookup_Error("Cipher specification '" + algo_spec +
"' is missing mode identifier");
const std::string mode = algo_parts[1];
#if defined(BOTAN_HAS_OFB)
if(mode == "OFB")
return new StreamCipher_Filter(new OFB(block_cipher->clone()));
#endif
#if defined(BOTAN_HAS_CTR_BE)
if(mode == "CTR-BE")
return new StreamCipher_Filter(new CTR_BE(block_cipher->clone()));
#endif
throw Algorithm_Not_Found(algo_spec);
}
/*
* Get a cipher object
*/
Keyed_Filter* get_cipher(const std::string& algo_spec,
const SymmetricKey& key,
const InitializationVector& iv,
Cipher_Dir direction)
{
Keyed_Filter* cipher = get_cipher(algo_spec, direction);
cipher->set_key(key);
if(iv.length())
cipher->set_iv(iv);
return cipher;
}
/*
* Get a cipher object
*/
Keyed_Filter* get_cipher(const std::string& algo_spec,
const SymmetricKey& key,
Cipher_Dir direction)
{
return get_cipher(algo_spec,
key, InitializationVector(), direction);
}
}
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