lion.cpp

Go to the documentation of this file.

/*
* Lion
* (C) 1999-2007 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/

#include <botan/lion.h>
#include <botan/internal/xor_buf.h>
#include <botan/parsing.h>

namespace Botan {

/*
* Lion Encryption
*/
void Lion::encrypt_n(const byte in[], byte out[], size_t blocks) const
   {
   secure_vector<byte> buffer_vec(LEFT_SIZE);
   byte* buffer = &buffer_vec[0];

   for(size_t i = 0; i != blocks; ++i)
      {
      xor_buf(buffer, in, &key1[0], LEFT_SIZE);
      cipher->set_key(buffer, LEFT_SIZE);
      cipher->cipher(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[0], LEFT_SIZE);
      cipher->set_key(buffer, LEFT_SIZE);
      cipher->cipher1(out + LEFT_SIZE, RIGHT_SIZE);

      in += BLOCK_SIZE;
      out += BLOCK_SIZE;
      }
   }

/*
* Lion Decryption
*/
void Lion::decrypt_n(const byte in[], byte out[], size_t blocks) const
   {
   secure_vector<byte> buffer_vec(LEFT_SIZE);
   byte* buffer = &buffer_vec[0];

   for(size_t i = 0; i != blocks; ++i)
      {
      xor_buf(buffer, in, &key2[0], LEFT_SIZE);
      cipher->set_key(buffer, LEFT_SIZE);
      cipher->cipher(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[0], LEFT_SIZE);
      cipher->set_key(buffer, LEFT_SIZE);
      cipher->cipher1(out + LEFT_SIZE, RIGHT_SIZE);

      in += BLOCK_SIZE;
      out += BLOCK_SIZE;
      }
   }

/*
* Lion Key Schedule
*/
void Lion::key_schedule(const byte key[], size_t length)
   {
   clear();

   key1.assign(key,                key + (length / 2));
   key2.assign(key + (length / 2), key + length);
   }

/*
* Return the name of this type
*/
std::string Lion::name() const
   {
   return "Lion(" + hash->name() + "," +
                    cipher->name() + "," +
                    std::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()
   {
   zap(key1);
   zap(key2);
   hash->clear();
   cipher->clear();
   }

/*
* Lion Constructor
*/
Lion::Lion(HashFunction* hash_in, StreamCipher* sc_in, size_t block_len) :
   BLOCK_SIZE(std::max<size_t>(2*hash_in->output_length() + 1, block_len)),
   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 Invalid_Argument(name() + ": This stream/hash combo is invalid");

   key1.resize(LEFT_SIZE);
   key2.resize(LEFT_SIZE);
   }

}