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/*
* Lion
* (C) 1999-2007,2014 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/internal/block_utils.h>
#include <botan/lion.h>
#include <botan/parsing.h>
#include <botan/libstate.h>
namespace Botan {
namespace {
Lion* make_lion(const BlockCipher::Spec& spec)
{
if(spec.arg_count_between(2, 3))
{
Algorithm_Factory& af = global_state().algorithm_factory();
const HashFunction* hash = af.prototype_hash_function(spec.arg(0));
const StreamCipher* stream_cipher = af.prototype_stream_cipher(spec.arg(1));
if(hash && stream_cipher)
{
const size_t block_size = spec.arg_as_integer(2, 1024);
return new Lion(hash->clone(), stream_cipher->clone(), block_size);
}
}
return nullptr;
}
}
BOTAN_REGISTER_NAMED_T(BlockCipher, "Lion", Lion, make_lion);
/*
* Lion Encryption
*/
void Lion::encrypt_n(const byte in[], byte out[], size_t blocks) const
{
const size_t LEFT_SIZE = left_size();
const size_t RIGHT_SIZE = right_size();
secure_vector<byte> buffer_vec(LEFT_SIZE);
byte* buffer = &buffer_vec[0];
for(size_t i = 0; i != blocks; ++i)
{
xor_buf(buffer, in, &m_key1[0], LEFT_SIZE);
m_cipher->set_key(buffer, LEFT_SIZE);
m_cipher->cipher(in + LEFT_SIZE, out + LEFT_SIZE, RIGHT_SIZE);
m_hash->update(out + LEFT_SIZE, RIGHT_SIZE);
m_hash->final(buffer);
xor_buf(out, in, buffer, LEFT_SIZE);
xor_buf(buffer, out, &m_key2[0], LEFT_SIZE);
m_cipher->set_key(buffer, LEFT_SIZE);
m_cipher->cipher1(out + LEFT_SIZE, RIGHT_SIZE);
in += m_block_size;
out += m_block_size;
}
}
/*
* Lion Decryption
*/
void Lion::decrypt_n(const byte in[], byte out[], size_t blocks) const
{
const size_t LEFT_SIZE = left_size();
const size_t RIGHT_SIZE = right_size();
secure_vector<byte> buffer_vec(LEFT_SIZE);
byte* buffer = &buffer_vec[0];
for(size_t i = 0; i != blocks; ++i)
{
xor_buf(buffer, in, &m_key2[0], LEFT_SIZE);
m_cipher->set_key(buffer, LEFT_SIZE);
m_cipher->cipher(in + LEFT_SIZE, out + LEFT_SIZE, RIGHT_SIZE);
m_hash->update(out + LEFT_SIZE, RIGHT_SIZE);
m_hash->final(buffer);
xor_buf(out, in, buffer, LEFT_SIZE);
xor_buf(buffer, out, &m_key1[0], LEFT_SIZE);
m_cipher->set_key(buffer, LEFT_SIZE);
m_cipher->cipher1(out + LEFT_SIZE, RIGHT_SIZE);
in += m_block_size;
out += m_block_size;
}
}
/*
* Lion Key Schedule
*/
void Lion::key_schedule(const byte key[], size_t length)
{
clear();
const size_t half = length / 2;
copy_mem(&m_key1[0], key, half);
copy_mem(&m_key2[0], key + half, half);
}
/*
* Return the name of this type
*/
std::string Lion::name() const
{
return "Lion(" + m_hash->name() + "," +
m_cipher->name() + "," +
std::to_string(block_size()) + ")";
}
/*
* Return a clone of this object
*/
BlockCipher* Lion::clone() const
{
return new Lion(m_hash->clone(), m_cipher->clone(), block_size());
}
/*
* Clear memory of sensitive data
*/
void Lion::clear()
{
zeroise(m_key1);
zeroise(m_key2);
m_hash->clear();
m_cipher->clear();
}
/*
* Lion Constructor
*/
Lion::Lion(HashFunction* hash, StreamCipher* cipher, size_t block_size) :
m_block_size(std::max<size_t>(2*hash->output_length() + 1, block_size)),
m_hash(hash),
m_cipher(cipher)
{
if(2*left_size() + 1 > m_block_size)
throw Invalid_Argument(name() + ": Chosen block size is too small");
if(!m_cipher->valid_keylength(left_size()))
throw Invalid_Argument(name() + ": This stream/hash combo is invalid");
m_key1.resize(left_size());
m_key2.resize(left_size());
}
}
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