/*************************************************
* Lion Source File                               *
* (C) 1999-2008 The Botan Project                *
*************************************************/

#include <botan/lion.h>
#include <botan/lookup.h>
#include <botan/bit_ops.h>
#include <botan/parsing.h>

namespace Botan {

/*************************************************
* Lion Encryption                                *
*************************************************/
void Lion::enc(const byte in[], byte out[]) const
   {
   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);
   }

/*************************************************
* Lion Decryption                                *
*************************************************/
void Lion::dec(const byte in[], byte out[]) const
   {
   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);
   }

/*************************************************
* Lion Key Schedule                              *
*************************************************/
void Lion::key(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->name(), cipher->name(), BLOCK_SIZE);
   }

/*************************************************
* Clear memory of sensitive data                 *
*************************************************/
void Lion::clear() throw()
   {
   hash->clear();
   cipher->clear();
   key1.clear();
   key2.clear();
   }

/*************************************************
* Lion Constructor                               *
*************************************************/
Lion::Lion(const std::string& hash_name, const std::string& sc_name,
           u32bit block_len) :
   BlockCipher(block_len, 2, 2*output_length_of(hash_name), 2),
   LEFT_SIZE(output_length_of(hash_name)), RIGHT_SIZE(BLOCK_SIZE - LEFT_SIZE)
   {
   hash = get_hash(hash_name);
   cipher = get_stream_cipher(sc_name);

   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);
   }

}