/*************************************************
* WiderWake Source File                          *
* (C) 1999-2007 The Botan Project                *
*************************************************/

#include <botan/wid_wake.h>
#include <botan/bit_ops.h>

namespace Botan {

/*************************************************
* Combine cipher stream with message             *
*************************************************/
void WiderWake_41_BE::cipher(const byte in[], byte out[], u32bit length)
   {
   while(length >= buffer.size() - position)
      {
      xor_buf(out, in, buffer + position, buffer.size() - position);
      length -= (buffer.size() - position);
      in += (buffer.size() - position);
      out += (buffer.size() - position);
      generate(buffer.size());
      }
   xor_buf(out, in, buffer + position, length);
   position += length;
   }

/*************************************************
* Generate cipher stream                         *
*************************************************/
void WiderWake_41_BE::generate(u32bit length)
   {
   u32bit R0 = state[0], R1 = state[1], R2 = state[2],
          R3 = state[3], R4 = state[4];

   for(u32bit j = 0; j != length; j += 8)
      {
      u32bit R0a;

      buffer[j+0] = get_byte(0, R3); buffer[j+1] = get_byte(1, R3);
      buffer[j+2] = get_byte(2, R3); buffer[j+3] = get_byte(3, R3);

      R0a = R4 + R3; R3 += R2; R2 += R1; R1 += R0;
      R0a = (R0a >> 8) ^ T[(R0a & 0xFF)];
      R1  = (R1  >> 8) ^ T[(R1  & 0xFF)];
      R2  = (R2  >> 8) ^ T[(R2  & 0xFF)];
      R3  = (R3  >> 8) ^ T[(R3  & 0xFF)];
      R4 = R0; R0 = R0a;

      buffer[j+4] = get_byte(0, R3); buffer[j+5] = get_byte(1, R3);
      buffer[j+6] = get_byte(2, R3); buffer[j+7] = get_byte(3, R3);

      R0a = R4 + R3; R3 += R2; R2 += R1; R1 += R0;
      R0a = (R0a >> 8) ^ T[(R0a & 0xFF)];
      R1  = (R1  >> 8) ^ T[(R1  & 0xFF)];
      R2  = (R2  >> 8) ^ T[(R2  & 0xFF)];
      R3  = (R3  >> 8) ^ T[(R3  & 0xFF)];
      R4 = R0; R0 = R0a;
      }
   state[0] = R0; state[1] = R1; state[2] = R2; state[3] = R3; state[4] = R4;
   position = 0;
   }

/*************************************************
* WiderWake Key Schedule                         *
*************************************************/
void WiderWake_41_BE::key(const byte key[], u32bit)
   {
   for(u32bit j = 0; j != 4; ++j)
      t_key[j] = make_u32bit(key[4*j], key[4*j+1], key[4*j+2], key[4*j+3]);

   static const u32bit MAGIC[8] = {
      0x726A8F3B, 0xE69A3B5C, 0xD3C71FE5, 0xAB3C73D2,
      0x4D3A8EB3, 0x0396D6E8, 0x3D4C2F7A, 0x9EE27CF3 };

   for(u32bit j = 0; j != 4; ++j)
      T[j] = t_key[j];
   for(u32bit j = 4; j != 256; ++j)
      {
      u32bit X = T[j-1] + T[j-4];
      T[j] = (X >> 3) ^ MAGIC[X % 8];
      }
   for(u32bit j = 0; j != 23; ++j)
      T[j] += T[j+89];

   u32bit X = T[33];
   u32bit Z = (T[59] | 0x01000001) & 0xFF7FFFFF;
   for(u32bit j = 0; j != 256; ++j)
      {
      X = (X & 0xFF7FFFFF) + Z;
      T[j] = (T[j] & 0x00FFFFFF) ^ X;
      }
   X = (T[X & 0xFF] ^ X) & 0xFF;
   Z = T[0];
   T[0] = T[X];
   for(u32bit j = 1; j != 256; ++j)
      {
      T[X] = T[j];
      X = (T[j ^ X] ^ X) & 0xFF;
      T[j] = T[X];
      }
   T[X] = Z;

   position = 0;
   const byte iv[8] = { 0 };
   resync(iv, 8);
   }

/*************************************************
* Resynchronization                              *
*************************************************/
void WiderWake_41_BE::resync(const byte iv[], u32bit length)
   {
   if(length != 8)
      throw Invalid_IV_Length(name(), length);

   for(u32bit j = 0; j != 4; ++j)
      state[j] = t_key[j];
   state[4] = make_u32bit(iv[0], iv[1], iv[2], iv[3]);
   state[0] ^= state[4];
   state[2] ^= make_u32bit(iv[4], iv[5], iv[6], iv[7]);

   generate(8*4);
   generate(buffer.size());
   }

/*************************************************
* Clear memory of sensitive data                 *
*************************************************/
void WiderWake_41_BE::clear() throw()
   {
   position = 0;
   t_key.clear();
   state.clear();
   T.clear();
   buffer.clear();
   }

}