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/*
* Lion
* (C) 1999-2007 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#include <botan/lion.h>
#include <botan/xor_buf.h>
#include <botan/parsing.h>
namespace Botan {
/*
* Lion Encryption
*/
void Lion::encrypt_n(const byte in[], byte out[], u32bit blocks) const
{
for(u32bit i = 0; i != blocks; ++i)
{
SecureVector<byte> buffer(LEFT_SIZE);
xor_buf(buffer, in, key1, LEFT_SIZE);
cipher->set_key(buffer, LEFT_SIZE);
cipher->encrypt(in + LEFT_SIZE, out + LEFT_SIZE, RIGHT_SIZE);
hash->update(out + LEFT_SIZE, RIGHT_SIZE);
hash->final(buffer);
xor_buf(out, in, buffer, LEFT_SIZE);
xor_buf(buffer, out, key2, LEFT_SIZE);
cipher->set_key(buffer, LEFT_SIZE);
cipher->encrypt(out + LEFT_SIZE, RIGHT_SIZE);
in += BLOCK_SIZE;
out += BLOCK_SIZE;
}
}
/*
* Lion Decryption
*/
void Lion::decrypt_n(const byte in[], byte out[], u32bit blocks) const
{
for(u32bit i = 0; i != blocks; ++i)
{
SecureVector<byte> buffer(LEFT_SIZE);
xor_buf(buffer, in, key2, LEFT_SIZE);
cipher->set_key(buffer, LEFT_SIZE);
cipher->encrypt(in + LEFT_SIZE, out + LEFT_SIZE, RIGHT_SIZE);
hash->update(out + LEFT_SIZE, RIGHT_SIZE);
hash->final(buffer);
xor_buf(out, in, buffer, LEFT_SIZE);
xor_buf(buffer, out, key1, LEFT_SIZE);
cipher->set_key(buffer, LEFT_SIZE);
cipher->encrypt(out + LEFT_SIZE, RIGHT_SIZE);
in += BLOCK_SIZE;
out += BLOCK_SIZE;
}
}
/*
* Lion Key Schedule
*/
void Lion::key_schedule(const byte key[], u32bit length)
{
clear();
key1.copy(key, length / 2);
key2.copy(key + length / 2, length / 2);
}
/*
* Return the name of this type
*/
std::string Lion::name() const
{
return "Lion(" + hash->name() + "," +
cipher->name() + "," +
to_string(BLOCK_SIZE) + ")";
}
/*
* Return a clone of this object
*/
BlockCipher* Lion::clone() const
{
return new Lion(hash->clone(), cipher->clone(), BLOCK_SIZE);
}
/*
* Clear memory of sensitive data
*/
void Lion::clear() throw()
{
hash->clear();
cipher->clear();
key1.clear();
key2.clear();
}
/*
* Lion Constructor
*/
Lion::Lion(HashFunction* hash_in, StreamCipher* sc_in, u32bit block_len) :
BlockCipher(std::max<u32bit>(2*hash_in->OUTPUT_LENGTH + 1, block_len),
2, 2*hash_in->OUTPUT_LENGTH, 2),
LEFT_SIZE(hash_in->OUTPUT_LENGTH),
RIGHT_SIZE(BLOCK_SIZE - LEFT_SIZE),
hash(hash_in),
cipher(sc_in)
{
if(2*LEFT_SIZE + 1 > BLOCK_SIZE)
throw Invalid_Argument(name() + ": Chosen block size is too small");
if(!cipher->valid_keylength(LEFT_SIZE))
throw Exception(name() + ": This stream/hash combination is invalid");
key1.create(LEFT_SIZE);
key2.create(LEFT_SIZE);
}
}
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