/*
* GOST 34.11
* (C) 2009 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/gost_3411.h>

namespace Botan {

/**
* GOST 34.11 Constructor
*/
GOST_34_11::GOST_34_11() :
   m_cipher(GOST_28147_89_Params("R3411_CryptoPro")),
   m_buffer(32),
   m_sum(32),
   m_hash(32)
   {
   m_count = 0;
   m_position = 0;
   }

void GOST_34_11::clear()
   {
   m_cipher.clear();
   zeroise(m_sum);
   zeroise(m_hash);
   m_count = 0;
   m_position = 0;
   }

std::unique_ptr<HashFunction> GOST_34_11::copy_state() const
   {
   return std::unique_ptr<HashFunction>(new GOST_34_11(*this));
   }

/**
* Hash additional inputs
*/
void GOST_34_11::add_data(const uint8_t input[], size_t length)
   {
   m_count += length;

   if(m_position)
      {
      buffer_insert(m_buffer, m_position, input, length);

      if(m_position + length >= hash_block_size())
         {
         compress_n(m_buffer.data(), 1);
         input += (hash_block_size() - m_position);
         length -= (hash_block_size() - m_position);
         m_position = 0;
         }
      }

   const size_t full_blocks = length / hash_block_size();
   const size_t remaining   = length % hash_block_size();

   if(full_blocks)
      compress_n(input, full_blocks);

   buffer_insert(m_buffer, m_position, input + full_blocks * hash_block_size(), remaining);
   m_position += remaining;
   }

/**
* The GOST 34.11 compression function
*/
void GOST_34_11::compress_n(const uint8_t input[], size_t blocks)
   {
   for(size_t i = 0; i != blocks; ++i)
      {
      for(uint16_t j = 0, carry = 0; j != 32; ++j)
         {
         uint16_t s = m_sum[j] + input[32*i+j] + carry;
         carry = get_byte(0, s);
         m_sum[j] = get_byte(1, s);
         }

      uint8_t S[32] = { 0 };

      uint64_t U[4], V[4];
      load_be(U, m_hash.data(), 4);
      load_be(V, input + 32*i, 4);

      for(size_t j = 0; j != 4; ++j)
         {
         uint8_t key[32] = { 0 };

         // P transformation
         for(size_t k = 0; k != 4; ++k)
            for(size_t l = 0; l != 8; ++l)
               key[4*l+k] = get_byte(l, U[k]) ^ get_byte(l, V[k]);

         m_cipher.set_key(key, 32);
         m_cipher.encrypt(&m_hash[8*j], S + 8*j);

         if(j == 3)
            break;

         // A(x)
         uint64_t A_U = U[0];
         U[0] = U[1];
         U[1] = U[2];
         U[2] = U[3];
         U[3] = U[0] ^ A_U;

         if(j == 1) // C_3
            {
            U[0] ^= 0x00FF00FF00FF00FF;
            U[1] ^= 0xFF00FF00FF00FF00;
            U[2] ^= 0x00FFFF00FF0000FF;
            U[3] ^= 0xFF000000FFFF00FF;
            }

         // A(A(x))
         uint64_t AA_V_1 = V[0] ^ V[1];
         uint64_t AA_V_2 = V[1] ^ V[2];
         V[0] = V[2];
         V[1] = V[3];
         V[2] = AA_V_1;
         V[3] = AA_V_2;
         }

      uint8_t S2[32] = { 0 };

      // 12 rounds of psi
      S2[ 0] = S[24];
      S2[ 1] = S[25];
      S2[ 2] = S[26];
      S2[ 3] = S[27];
      S2[ 4] = S[28];
      S2[ 5] = S[29];
      S2[ 6] = S[30];
      S2[ 7] = S[31];
      S2[ 8] = S[ 0] ^ S[ 2] ^ S[ 4] ^ S[ 6] ^ S[24] ^ S[30];
      S2[ 9] = S[ 1] ^ S[ 3] ^ S[ 5] ^ S[ 7] ^ S[25] ^ S[31];
      S2[10] = S[ 0] ^ S[ 8] ^ S[24] ^ S[26] ^ S[30];
      S2[11] = S[ 1] ^ S[ 9] ^ S[25] ^ S[27] ^ S[31];
      S2[12] = S[ 0] ^ S[ 4] ^ S[ 6] ^ S[10] ^ S[24] ^ S[26] ^ S[28] ^ S[30];
      S2[13] = S[ 1] ^ S[ 5] ^ S[ 7] ^ S[11] ^ S[25] ^ S[27] ^ S[29] ^ S[31];
      S2[14] = S[ 0] ^ S[ 4] ^ S[ 8] ^ S[12] ^ S[24] ^ S[26] ^ S[28];
      S2[15] = S[ 1] ^ S[ 5] ^ S[ 9] ^ S[13] ^ S[25] ^ S[27] ^ S[29];
      S2[16] = S[ 2] ^ S[ 6] ^ S[10] ^ S[14] ^ S[26] ^ S[28] ^ S[30];
      S2[17] = S[ 3] ^ S[ 7] ^ S[11] ^ S[15] ^ S[27] ^ S[29] ^ S[31];
      S2[18] = S[ 0] ^ S[ 2] ^ S[ 6] ^ S[ 8] ^ S[12] ^ S[16] ^ S[24] ^ S[28];
      S2[19] = S[ 1] ^ S[ 3] ^ S[ 7] ^ S[ 9] ^ S[13] ^ S[17] ^ S[25] ^ S[29];
      S2[20] = S[ 2] ^ S[ 4] ^ S[ 8] ^ S[10] ^ S[14] ^ S[18] ^ S[26] ^ S[30];
      S2[21] = S[ 3] ^ S[ 5] ^ S[ 9] ^ S[11] ^ S[15] ^ S[19] ^ S[27] ^ S[31];
      S2[22] = S[ 0] ^ S[ 2] ^ S[10] ^ S[12] ^ S[16] ^ S[20] ^ S[24] ^ S[28] ^ S[30];
      S2[23] = S[ 1] ^ S[ 3] ^ S[11] ^ S[13] ^ S[17] ^ S[21] ^ S[25] ^ S[29] ^ S[31];
      S2[24] = S[ 0] ^ S[ 6] ^ S[12] ^ S[14] ^ S[18] ^ S[22] ^ S[24] ^ S[26];
      S2[25] = S[ 1] ^ S[ 7] ^ S[13] ^ S[15] ^ S[19] ^ S[23] ^ S[25] ^ S[27];
      S2[26] = S[ 2] ^ S[ 8] ^ S[14] ^ S[16] ^ S[20] ^ S[24] ^ S[26] ^ S[28];
      S2[27] = S[ 3] ^ S[ 9] ^ S[15] ^ S[17] ^ S[21] ^ S[25] ^ S[27] ^ S[29];
      S2[28] = S[ 4] ^ S[10] ^ S[16] ^ S[18] ^ S[22] ^ S[26] ^ S[28] ^ S[30];
      S2[29] = S[ 5] ^ S[11] ^ S[17] ^ S[19] ^ S[23] ^ S[27] ^ S[29] ^ S[31];
      S2[30] = S[ 0] ^ S[ 2] ^ S[ 4] ^ S[12] ^ S[18] ^ S[20] ^ S[28];
      S2[31] = S[ 1] ^ S[ 3] ^ S[ 5] ^ S[13] ^ S[19] ^ S[21] ^ S[29];

      xor_buf(S, S2, input + 32*i, 32);

      S2[0] = S[0] ^ S[2] ^ S[4] ^ S[6] ^ S[24] ^ S[30];
      S2[1] = S[1] ^ S[3] ^ S[5] ^ S[7] ^ S[25] ^ S[31];

      copy_mem(S, S+2, 30);
      S[30] = S2[0];
      S[31] = S2[1];

      xor_buf(S, m_hash.data(), 32);

      // 61 rounds of psi
      S2[ 0] = S[ 2] ^ S[ 6] ^ S[14] ^ S[20] ^ S[22] ^ S[26] ^ S[28] ^ S[30];
      S2[ 1] = S[ 3] ^ S[ 7] ^ S[15] ^ S[21] ^ S[23] ^ S[27] ^ S[29] ^ S[31];
      S2[ 2] = S[ 0] ^ S[ 2] ^ S[ 6] ^ S[ 8] ^ S[16] ^ S[22] ^ S[28];
      S2[ 3] = S[ 1] ^ S[ 3] ^ S[ 7] ^ S[ 9] ^ S[17] ^ S[23] ^ S[29];
      S2[ 4] = S[ 2] ^ S[ 4] ^ S[ 8] ^ S[10] ^ S[18] ^ S[24] ^ S[30];
      S2[ 5] = S[ 3] ^ S[ 5] ^ S[ 9] ^ S[11] ^ S[19] ^ S[25] ^ S[31];
      S2[ 6] = S[ 0] ^ S[ 2] ^ S[10] ^ S[12] ^ S[20] ^ S[24] ^ S[26] ^ S[30];
      S2[ 7] = S[ 1] ^ S[ 3] ^ S[11] ^ S[13] ^ S[21] ^ S[25] ^ S[27] ^ S[31];
      S2[ 8] = S[ 0] ^ S[ 6] ^ S[12] ^ S[14] ^ S[22] ^ S[24] ^ S[26] ^ S[28] ^ S[30];
      S2[ 9] = S[ 1] ^ S[ 7] ^ S[13] ^ S[15] ^ S[23] ^ S[25] ^ S[27] ^ S[29] ^ S[31];
      S2[10] = S[ 0] ^ S[ 4] ^ S[ 6] ^ S[ 8] ^ S[14] ^ S[16] ^ S[26] ^ S[28];
      S2[11] = S[ 1] ^ S[ 5] ^ S[ 7] ^ S[ 9] ^ S[15] ^ S[17] ^ S[27] ^ S[29];
      S2[12] = S[ 2] ^ S[ 6] ^ S[ 8] ^ S[10] ^ S[16] ^ S[18] ^ S[28] ^ S[30];
      S2[13] = S[ 3] ^ S[ 7] ^ S[ 9] ^ S[11] ^ S[17] ^ S[19] ^ S[29] ^ S[31];
      S2[14] = S[ 0] ^ S[ 2] ^ S[ 6] ^ S[ 8] ^ S[10] ^ S[12] ^ S[18] ^ S[20] ^ S[24];
      S2[15] = S[ 1] ^ S[ 3] ^ S[ 7] ^ S[ 9] ^ S[11] ^ S[13] ^ S[19] ^ S[21] ^ S[25];
      S2[16] = S[ 2] ^ S[ 4] ^ S[ 8] ^ S[10] ^ S[12] ^ S[14] ^ S[20] ^ S[22] ^ S[26];
      S2[17] = S[ 3] ^ S[ 5] ^ S[ 9] ^ S[11] ^ S[13] ^ S[15] ^ S[21] ^ S[23] ^ S[27];
      S2[18] = S[ 4] ^ S[ 6] ^ S[10] ^ S[12] ^ S[14] ^ S[16] ^ S[22] ^ S[24] ^ S[28];
      S2[19] = S[ 5] ^ S[ 7] ^ S[11] ^ S[13] ^ S[15] ^ S[17] ^ S[23] ^ S[25] ^ S[29];
      S2[20] = S[ 6] ^ S[ 8] ^ S[12] ^ S[14] ^ S[16] ^ S[18] ^ S[24] ^ S[26] ^ S[30];
      S2[21] = S[ 7] ^ S[ 9] ^ S[13] ^ S[15] ^ S[17] ^ S[19] ^ S[25] ^ S[27] ^ S[31];
      S2[22] = S[ 0] ^ S[ 2] ^ S[ 4] ^ S[ 6] ^ S[ 8] ^ S[10] ^ S[14] ^ S[16] ^
               S[18] ^ S[20] ^ S[24] ^ S[26] ^ S[28] ^ S[30];
      S2[23] = S[ 1] ^ S[ 3] ^ S[ 5] ^ S[ 7] ^ S[ 9] ^ S[11] ^ S[15] ^ S[17] ^
               S[19] ^ S[21] ^ S[25] ^ S[27] ^ S[29] ^ S[31];
      S2[24] = S[ 0] ^ S[ 8] ^ S[10] ^ S[12] ^ S[16] ^ S[18] ^ S[20] ^ S[22] ^
               S[24] ^ S[26] ^ S[28];
      S2[25] = S[ 1] ^ S[ 9] ^ S[11] ^ S[13] ^ S[17] ^ S[19] ^ S[21] ^ S[23] ^
               S[25] ^ S[27] ^ S[29];
      S2[26] = S[ 2] ^ S[10] ^ S[12] ^ S[14] ^ S[18] ^ S[20] ^ S[22] ^ S[24] ^
               S[26] ^ S[28] ^ S[30];
      S2[27] = S[ 3] ^ S[11] ^ S[13] ^ S[15] ^ S[19] ^ S[21] ^ S[23] ^ S[25] ^
               S[27] ^ S[29] ^ S[31];
      S2[28] = S[ 0] ^ S[ 2] ^ S[ 6] ^ S[12] ^ S[14] ^ S[16] ^ S[20] ^ S[22] ^ S[26] ^ S[28];
      S2[29] = S[ 1] ^ S[ 3] ^ S[ 7] ^ S[13] ^ S[15] ^ S[17] ^ S[21] ^ S[23] ^ S[27] ^ S[29];
      S2[30] = S[ 2] ^ S[ 4] ^ S[ 8] ^ S[14] ^ S[16] ^ S[18] ^ S[22] ^ S[24] ^ S[28] ^ S[30];
      S2[31] = S[ 3] ^ S[ 5] ^ S[ 9] ^ S[15] ^ S[17] ^ S[19] ^ S[23] ^ S[25] ^ S[29] ^ S[31];

      copy_mem(m_hash.data(), S2, 32);
      }
   }

/**
* Produce the final GOST 34.11 output
*/
void GOST_34_11::final_result(uint8_t out[])
   {
   if(m_position)
      {
      clear_mem(m_buffer.data() + m_position, m_buffer.size() - m_position);
      compress_n(m_buffer.data(), 1);
      }

   secure_vector<uint8_t> length_buf(32);
   const uint64_t bit_count = m_count * 8;
   store_le(bit_count, length_buf.data());

   secure_vector<uint8_t> sum_buf = m_sum;

   compress_n(length_buf.data(), 1);
   compress_n(sum_buf.data(), 1);

   copy_mem(out, m_hash.data(), 32);

   clear();
   }

}