/*

 * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>

 *

 * Permission is hereby granted, free of charge, to any person obtaining 

 * a copy of this software and associated documentation files (the

 * "Software"), to deal in the Software without restriction, including

 * without limitation the rights to use, copy, modify, merge, publish,

 * distribute, sublicense, and/or sell copies of the Software, and to

 * permit persons to whom the Software is furnished to do so, subject to

 * the following conditions:

 *

 * The above copyright notice and this permission notice shall be 

 * included in all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 

 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 

 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS

 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN

 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

 * SOFTWARE.

 */

#include "inner.h"

static inline void

add_round_key(uint32_t *q, const uint32_t *sk)

{

  q[0] ^= sk[0];

  q[1] ^= sk[1];

  q[2] ^= sk[2];

  q[3] ^= sk[3];

  q[4] ^= sk[4];

  q[5] ^= sk[5];

  q[6] ^= sk[6];

  q[7] ^= sk[7];

}

static inline void

shift_rows(uint32_t *q)

{

  int i;

  for (i = 0; i < 8; i ++) {

    uint32_t x;

    x = q[i];

    q[i] = (x & 0x000000FF)

      | ((x & 0x0000FC00) >> 2) | ((x & 0x00000300) << 6)

      | ((x & 0x00F00000) >> 4) | ((x & 0x000F0000) << 4)

      | ((x & 0xC0000000) >> 6) | ((x & 0x3F000000) << 2);

  }

}

static inline uint32_t

rotr16(uint32_t x)

{

  return (x << 16) | (x >> 16);

}

static inline void

mix_columns(uint32_t *q)

{

  uint32_t q0, q1, q2, q3, q4, q5, q6, q7;

  uint32_t r0, r1, r2, r3, r4, r5, r6, r7;

  q0 = q[0];

  q1 = q[1];

  q2 = q[2];

  q3 = q[3];

  q4 = q[4];

  q5 = q[5];

  q6 = q[6];

  q7 = q[7];

  r0 = (q0 >> 8) | (q0 << 24);

  r1 = (q1 >> 8) | (q1 << 24);

  r2 = (q2 >> 8) | (q2 << 24);

  r3 = (q3 >> 8) | (q3 << 24);

  r4 = (q4 >> 8) | (q4 << 24);

  r5 = (q5 >> 8) | (q5 << 24);

  r6 = (q6 >> 8) | (q6 << 24);

  r7 = (q7 >> 8) | (q7 << 24);

  q[0] = q7 ^ r7 ^ r0 ^ rotr16(q0 ^ r0);

  q[1] = q0 ^ r0 ^ q7 ^ r7 ^ r1 ^ rotr16(q1 ^ r1);

  q[2] = q1 ^ r1 ^ r2 ^ rotr16(q2 ^ r2);

  q[3] = q2 ^ r2 ^ q7 ^ r7 ^ r3 ^ rotr16(q3 ^ r3);

  q[4] = q3 ^ r3 ^ q7 ^ r7 ^ r4 ^ rotr16(q4 ^ r4);

  q[5] = q4 ^ r4 ^ r5 ^ rotr16(q5 ^ r5);

  q[6] = q5 ^ r5 ^ r6 ^ rotr16(q6 ^ r6);

  q[7] = q6 ^ r6 ^ r7 ^ rotr16(q7 ^ r7);

}

/* see inner.h */

void

br_aes_ct_bitslice_encrypt(unsigned num_rounds,

  const uint32_t *skey, uint32_t *q)

{

  unsigned u;

  add_round_key(q, skey);

  for (u = 1; u < num_rounds; u ++) {

    br_aes_ct_bitslice_Sbox(q);

    shift_rows(q);

    mix_columns(q);

    add_round_key(q, skey + (u << 3));

  }

  br_aes_ct_bitslice_Sbox(q);

  shift_rows(q);

  add_round_key(q, skey + (num_rounds << 3));

}