/*

* Twofish

* (C) 1999-2007,2017 Jack Lloyd

*

* The key schedule implemenation is based on a public domain

* implementation by Matthew Skala

*

* Botan is released under the Simplified BSD License (see license.txt)

*/

#include <botan/internal/twofish.h>

#include <botan/internal/loadstor.h>

#include <botan/internal/rotate.h>

namespace Botan {

namespace {

inline void TF_E(

   uint32_t A, uint32_t B, uint32_t& C, uint32_t& D, uint32_t RK1, uint32_t RK2, const secure_vector<uint32_t>& SB) {

   uint32_t X = SB[get_byte<3>(A)] ^ SB[256 + get_byte<2>(A)] ^ SB[512 + get_byte<1>(A)] ^ SB[768 + get_byte<0>(A)];

   uint32_t Y = SB[get_byte<0>(B)] ^ SB[256 + get_byte<3>(B)] ^ SB[512 + get_byte<2>(B)] ^ SB[768 + get_byte<1>(B)];

   X += Y;

   Y += X;

   X += RK1;

   Y += RK2;

   C = rotr<1>(C ^ X);

   D = rotl<1>(D) ^ Y;

}

inline void TF_D(

   uint32_t A, uint32_t B, uint32_t& C, uint32_t& D, uint32_t RK1, uint32_t RK2, const secure_vector<uint32_t>& SB) {

   uint32_t X = SB[get_byte<3>(A)] ^ SB[256 + get_byte<2>(A)] ^ SB[512 + get_byte<1>(A)] ^ SB[768 + get_byte<0>(A)];

   uint32_t Y = SB[get_byte<0>(B)] ^ SB[256 + get_byte<3>(B)] ^ SB[512 + get_byte<2>(B)] ^ SB[768 + get_byte<1>(B)];

   X += Y;

   Y += X;

   X += RK1;

   Y += RK2;

   C = rotl<1>(C) ^ X;

   D = rotr<1>(D ^ Y);

}

}  // namespace

/*

* Twofish Encryption

*/

void Twofish::encrypt_n(const uint8_t in[], uint8_t out[], size_t blocks) const {

   assert_key_material_set();

   while(blocks >= 2) {

      uint32_t A0, B0, C0, D0;

      uint32_t A1, B1, C1, D1;

      load_le(in, A0, B0, C0, D0, A1, B1, C1, D1);

      A0 ^= m_RK[0];

      A1 ^= m_RK[0];

      B0 ^= m_RK[1];

      B1 ^= m_RK[1];

      C0 ^= m_RK[2];

      C1 ^= m_RK[2];

      D0 ^= m_RK[3];

      D1 ^= m_RK[3];

      for(size_t k = 8; k != 40; k += 4) {

         TF_E(A0, B0, C0, D0, m_RK[k + 0], m_RK[k + 1], m_SB);

         TF_E(A1, B1, C1, D1, m_RK[k + 0], m_RK[k + 1], m_SB);

         TF_E(C0, D0, A0, B0, m_RK[k + 2], m_RK[k + 3], m_SB);

         TF_E(C1, D1, A1, B1, m_RK[k + 2], m_RK[k + 3], m_SB);

      }

      C0 ^= m_RK[4];

      C1 ^= m_RK[4];

      D0 ^= m_RK[5];

      D1 ^= m_RK[5];

      A0 ^= m_RK[6];

      A1 ^= m_RK[6];

      B0 ^= m_RK[7];

      B1 ^= m_RK[7];

      store_le(out, C0, D0, A0, B0, C1, D1, A1, B1);

      blocks -= 2;

      out += 2 * BLOCK_SIZE;

      in += 2 * BLOCK_SIZE;

   }

   if(blocks) {

      uint32_t A, B, C, D;

      load_le(in, A, B, C, D);

      A ^= m_RK[0];

      B ^= m_RK[1];

      C ^= m_RK[2];

      D ^= m_RK[3];

      for(size_t k = 8; k != 40; k += 4) {

         TF_E(A, B, C, D, m_RK[k], m_RK[k + 1], m_SB);

         TF_E(C, D, A, B, m_RK[k + 2], m_RK[k + 3], m_SB);

      }

      C ^= m_RK[4];

      D ^= m_RK[5];

      A ^= m_RK[6];

      B ^= m_RK[7];

      store_le(out, C, D, A, B);

   }

}

/*

* Twofish Decryption

*/

void Twofish::decrypt_n(const uint8_t in[], uint8_t out[], size_t blocks) const {

   assert_key_material_set();

   while(blocks >= 2) {

      uint32_t A0, B0, C0, D0;

      uint32_t A1, B1, C1, D1;

      load_le(in, A0, B0, C0, D0, A1, B1, C1, D1);

      A0 ^= m_RK[4];

      A1 ^= m_RK[4];

      B0 ^= m_RK[5];

      B1 ^= m_RK[5];

      C0 ^= m_RK[6];

      C1 ^= m_RK[6];

      D0 ^= m_RK[7];

      D1 ^= m_RK[7];

      for(size_t k = 40; k != 8; k -= 4) {

         TF_D(A0, B0, C0, D0, m_RK[k - 2], m_RK[k - 1], m_SB);

         TF_D(A1, B1, C1, D1, m_RK[k - 2], m_RK[k - 1], m_SB);

         TF_D(C0, D0, A0, B0, m_RK[k - 4], m_RK[k - 3], m_SB);

         TF_D(C1, D1, A1, B1, m_RK[k - 4], m_RK[k - 3], m_SB);

      }

      C0 ^= m_RK[0];

      C1 ^= m_RK[0];

      D0 ^= m_RK[1];

      D1 ^= m_RK[1];

      A0 ^= m_RK[2];

      A1 ^= m_RK[2];

      B0 ^= m_RK[3];

      B1 ^= m_RK[3];

      store_le(out, C0, D0, A0, B0, C1, D1, A1, B1);

      blocks -= 2;

      out += 2 * BLOCK_SIZE;

      in += 2 * BLOCK_SIZE;

   }

   if(blocks) {

      uint32_t A, B, C, D;

      load_le(in, A, B, C, D);

      A ^= m_RK[4];

      B ^= m_RK[5];

      C ^= m_RK[6];

      D ^= m_RK[7];

      for(size_t k = 40; k != 8; k -= 4) {

         TF_D(A, B, C, D, m_RK[k - 2], m_RK[k - 1], m_SB);

         TF_D(C, D, A, B, m_RK[k - 4], m_RK[k - 3], m_SB);

      }

      C ^= m_RK[0];

      D ^= m_RK[1];

      A ^= m_RK[2];

      B ^= m_RK[3];

      store_le(out, C, D, A, B);

   }

}

bool Twofish::has_keying_material() const {

   return !m_SB.empty();

}

/*

* Twofish Key Schedule

*/

void Twofish::key_schedule(std::span<const uint8_t> key) {

   m_SB.resize(1024);

   m_RK.resize(40);

   secure_vector<uint8_t> S(16);

   for(size_t i = 0; i != key.size(); ++i) {

      /*

      * Do one column of the RS matrix multiplcation

      */

      if(key[i]) {

         uint8_t X = POLY_TO_EXP[key[i] - 1];

         uint8_t RS1 = RS[(4 * i) % 32];

         uint8_t RS2 = RS[(4 * i + 1) % 32];

         uint8_t RS3 = RS[(4 * i + 2) % 32];

         uint8_t RS4 = RS[(4 * i + 3) % 32];

         S[4 * (i / 8)] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS1 - 1]) % 255];

         S[4 * (i / 8) + 1] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS2 - 1]) % 255];

         S[4 * (i / 8) + 2] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS3 - 1]) % 255];

         S[4 * (i / 8) + 3] ^= EXP_TO_POLY[(X + POLY_TO_EXP[RS4 - 1]) % 255];

      }

   }

   if(key.size() == 16) {

      for(size_t i = 0; i != 256; ++i) {

         m_SB[i] = MDS0[Q0[Q0[i] ^ S[0]] ^ S[4]];

         m_SB[256 + i] = MDS1[Q0[Q1[i] ^ S[1]] ^ S[5]];

         m_SB[512 + i] = MDS2[Q1[Q0[i] ^ S[2]] ^ S[6]];

         m_SB[768 + i] = MDS3[Q1[Q1[i] ^ S[3]] ^ S[7]];

      }

      for(size_t i = 0; i < 40; i += 2) {

         uint32_t X = MDS0[Q0[Q0[i] ^ key[8]] ^ key[0]] ^ MDS1[Q0[Q1[i] ^ key[9]] ^ key[1]] ^

                      MDS2[Q1[Q0[i] ^ key[10]] ^ key[2]] ^ MDS3[Q1[Q1[i] ^ key[11]] ^ key[3]];

         uint32_t Y = MDS0[Q0[Q0[i + 1] ^ key[12]] ^ key[4]] ^ MDS1[Q0[Q1[i + 1] ^ key[13]] ^ key[5]] ^

                      MDS2[Q1[Q0[i + 1] ^ key[14]] ^ key[6]] ^ MDS3[Q1[Q1[i + 1] ^ key[15]] ^ key[7]];

         Y = rotl<8>(Y);

         X += Y;

         Y += X;

         m_RK[i] = X;

         m_RK[i + 1] = rotl<9>(Y);

      }

   } else if(key.size() == 24) {

      for(size_t i = 0; i != 256; ++i) {

         m_SB[i] = MDS0[Q0[Q0[Q1[i] ^ S[0]] ^ S[4]] ^ S[8]];

         m_SB[256 + i] = MDS1[Q0[Q1[Q1[i] ^ S[1]] ^ S[5]] ^ S[9]];

         m_SB[512 + i] = MDS2[Q1[Q0[Q0[i] ^ S[2]] ^ S[6]] ^ S[10]];

         m_SB[768 + i] = MDS3[Q1[Q1[Q0[i] ^ S[3]] ^ S[7]] ^ S[11]];

      }

      for(size_t i = 0; i < 40; i += 2) {

         uint32_t X =

            MDS0[Q0[Q0[Q1[i] ^ key[16]] ^ key[8]] ^ key[0]] ^ MDS1[Q0[Q1[Q1[i] ^ key[17]] ^ key[9]] ^ key[1]] ^

            MDS2[Q1[Q0[Q0[i] ^ key[18]] ^ key[10]] ^ key[2]] ^ MDS3[Q1[Q1[Q0[i] ^ key[19]] ^ key[11]] ^ key[3]];

         uint32_t Y = MDS0[Q0[Q0[Q1[i + 1] ^ key[20]] ^ key[12]] ^ key[4]] ^

                      MDS1[Q0[Q1[Q1[i + 1] ^ key[21]] ^ key[13]] ^ key[5]] ^

                      MDS2[Q1[Q0[Q0[i + 1] ^ key[22]] ^ key[14]] ^ key[6]] ^

                      MDS3[Q1[Q1[Q0[i + 1] ^ key[23]] ^ key[15]] ^ key[7]];

         Y = rotl<8>(Y);

         X += Y;

         Y += X;

         m_RK[i] = X;

         m_RK[i + 1] = rotl<9>(Y);

      }

   } else if(key.size() == 32) {

      for(size_t i = 0; i != 256; ++i) {

         m_SB[i] = MDS0[Q0[Q0[Q1[Q1[i] ^ S[0]] ^ S[4]] ^ S[8]] ^ S[12]];

         m_SB[256 + i] = MDS1[Q0[Q1[Q1[Q0[i] ^ S[1]] ^ S[5]] ^ S[9]] ^ S[13]];

         m_SB[512 + i] = MDS2[Q1[Q0[Q0[Q0[i] ^ S[2]] ^ S[6]] ^ S[10]] ^ S[14]];

         m_SB[768 + i] = MDS3[Q1[Q1[Q0[Q1[i] ^ S[3]] ^ S[7]] ^ S[11]] ^ S[15]];

      }

      for(size_t i = 0; i < 40; i += 2) {

         uint32_t X = MDS0[Q0[Q0[Q1[Q1[i] ^ key[24]] ^ key[16]] ^ key[8]] ^ key[0]] ^

                      MDS1[Q0[Q1[Q1[Q0[i] ^ key[25]] ^ key[17]] ^ key[9]] ^ key[1]] ^

                      MDS2[Q1[Q0[Q0[Q0[i] ^ key[26]] ^ key[18]] ^ key[10]] ^ key[2]] ^

                      MDS3[Q1[Q1[Q0[Q1[i] ^ key[27]] ^ key[19]] ^ key[11]] ^ key[3]];

         uint32_t Y = MDS0[Q0[Q0[Q1[Q1[i + 1] ^ key[28]] ^ key[20]] ^ key[12]] ^ key[4]] ^

                      MDS1[Q0[Q1[Q1[Q0[i + 1] ^ key[29]] ^ key[21]] ^ key[13]] ^ key[5]] ^

                      MDS2[Q1[Q0[Q0[Q0[i + 1] ^ key[30]] ^ key[22]] ^ key[14]] ^ key[6]] ^

                      MDS3[Q1[Q1[Q0[Q1[i + 1] ^ key[31]] ^ key[23]] ^ key[15]] ^ key[7]];

         Y = rotl<8>(Y);

         X += Y;

         Y += X;

         m_RK[i] = X;

         m_RK[i + 1] = rotl<9>(Y);

      }

   }

}

/*

* Clear memory of sensitive data

*/

void Twofish::clear() {

   zap(m_SB);

   zap(m_RK);

}

}  // namespace Botan