/*

 * 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"

/* see inner.h */

void

br_aes_ct_bitslice_Sbox(uint32_t *q)

{

  /*

   * This S-box implementation is a straightforward translation of

   * the circuit described by Boyar and Peralta in "A new

   * combinational logic minimization technique with applications

   * to cryptology" (https://eprint.iacr.org/2009/191.pdf).

   *

   * Note that variables x* (input) and s* (output) are numbered

   * in "reverse" order (x0 is the high bit, x7 is the low bit).

   */

  uint32_t x0, x1, x2, x3, x4, x5, x6, x7;

  uint32_t y1, y2, y3, y4, y5, y6, y7, y8, y9;

  uint32_t y10, y11, y12, y13, y14, y15, y16, y17, y18, y19;

  uint32_t y20, y21;

  uint32_t z0, z1, z2, z3, z4, z5, z6, z7, z8, z9;

  uint32_t z10, z11, z12, z13, z14, z15, z16, z17;

  uint32_t t0, t1, t2, t3, t4, t5, t6, t7, t8, t9;

  uint32_t t10, t11, t12, t13, t14, t15, t16, t17, t18, t19;

  uint32_t t20, t21, t22, t23, t24, t25, t26, t27, t28, t29;

  uint32_t t30, t31, t32, t33, t34, t35, t36, t37, t38, t39;

  uint32_t t40, t41, t42, t43, t44, t45, t46, t47, t48, t49;

  uint32_t t50, t51, t52, t53, t54, t55, t56, t57, t58, t59;

  uint32_t t60, t61, t62, t63, t64, t65, t66, t67;

  uint32_t s0, s1, s2, s3, s4, s5, s6, s7;

  x0 = q[7];

  x1 = q[6];

  x2 = q[5];

  x3 = q[4];

  x4 = q[3];

  x5 = q[2];

  x6 = q[1];

  x7 = q[0];

  /*

   * Top linear transformation.

   */

  y14 = x3 ^ x5;

  y13 = x0 ^ x6;

  y9 = x0 ^ x3;

  y8 = x0 ^ x5;

  t0 = x1 ^ x2;

  y1 = t0 ^ x7;

  y4 = y1 ^ x3;

  y12 = y13 ^ y14;

  y2 = y1 ^ x0;

  y5 = y1 ^ x6;

  y3 = y5 ^ y8;

  t1 = x4 ^ y12;

  y15 = t1 ^ x5;

  y20 = t1 ^ x1;

  y6 = y15 ^ x7;

  y10 = y15 ^ t0;

  y11 = y20 ^ y9;

  y7 = x7 ^ y11;

  y17 = y10 ^ y11;

  y19 = y10 ^ y8;

  y16 = t0 ^ y11;

  y21 = y13 ^ y16;

  y18 = x0 ^ y16;

  /*

   * Non-linear section.

   */

  t2 = y12 & y15;

  t3 = y3 & y6;

  t4 = t3 ^ t2;

  t5 = y4 & x7;

  t6 = t5 ^ t2;

  t7 = y13 & y16;

  t8 = y5 & y1;

  t9 = t8 ^ t7;

  t10 = y2 & y7;

  t11 = t10 ^ t7;

  t12 = y9 & y11;

  t13 = y14 & y17;

  t14 = t13 ^ t12;

  t15 = y8 & y10;

  t16 = t15 ^ t12;

  t17 = t4 ^ t14;

  t18 = t6 ^ t16;

  t19 = t9 ^ t14;

  t20 = t11 ^ t16;

  t21 = t17 ^ y20;

  t22 = t18 ^ y19;

  t23 = t19 ^ y21;

  t24 = t20 ^ y18;

  t25 = t21 ^ t22;

  t26 = t21 & t23;

  t27 = t24 ^ t26;

  t28 = t25 & t27;

  t29 = t28 ^ t22;

  t30 = t23 ^ t24;

  t31 = t22 ^ t26;

  t32 = t31 & t30;

  t33 = t32 ^ t24;

  t34 = t23 ^ t33;

  t35 = t27 ^ t33;

  t36 = t24 & t35;

  t37 = t36 ^ t34;

  t38 = t27 ^ t36;

  t39 = t29 & t38;

  t40 = t25 ^ t39;

  t41 = t40 ^ t37;

  t42 = t29 ^ t33;

  t43 = t29 ^ t40;

  t44 = t33 ^ t37;

  t45 = t42 ^ t41;

  z0 = t44 & y15;

  z1 = t37 & y6;

  z2 = t33 & x7;

  z3 = t43 & y16;

  z4 = t40 & y1;

  z5 = t29 & y7;

  z6 = t42 & y11;

  z7 = t45 & y17;

  z8 = t41 & y10;

  z9 = t44 & y12;

  z10 = t37 & y3;

  z11 = t33 & y4;

  z12 = t43 & y13;

  z13 = t40 & y5;

  z14 = t29 & y2;

  z15 = t42 & y9;

  z16 = t45 & y14;

  z17 = t41 & y8;

  /*

   * Bottom linear transformation.

   */

  t46 = z15 ^ z16;

  t47 = z10 ^ z11;

  t48 = z5 ^ z13;

  t49 = z9 ^ z10;

  t50 = z2 ^ z12;

  t51 = z2 ^ z5;

  t52 = z7 ^ z8;

  t53 = z0 ^ z3;

  t54 = z6 ^ z7;

  t55 = z16 ^ z17;

  t56 = z12 ^ t48;

  t57 = t50 ^ t53;

  t58 = z4 ^ t46;

  t59 = z3 ^ t54;

  t60 = t46 ^ t57;

  t61 = z14 ^ t57;

  t62 = t52 ^ t58;

  t63 = t49 ^ t58;

  t64 = z4 ^ t59;

  t65 = t61 ^ t62;

  t66 = z1 ^ t63;

  s0 = t59 ^ t63;

  s6 = t56 ^ ~t62;

  s7 = t48 ^ ~t60;

  t67 = t64 ^ t65;

  s3 = t53 ^ t66;

  s4 = t51 ^ t66;

  s5 = t47 ^ t65;

  s1 = t64 ^ ~s3;

  s2 = t55 ^ ~t67;

  q[7] = s0;

  q[6] = s1;

  q[5] = s2;

  q[4] = s3;

  q[3] = s4;

  q[2] = s5;

  q[1] = s6;

  q[0] = s7;

}

/* see inner.h */

void

br_aes_ct_ortho(uint32_t *q)

{

#define SWAPN(cl, ch, s, x, y)   do { \

    uint32_t a, b; \

    a = (x); \

    b = (y); \

    (x) = (a & (uint32_t)cl) | ((b & (uint32_t)cl) << (s)); \

    (y) = ((a & (uint32_t)ch) >> (s)) | (b & (uint32_t)ch); \

  } while (0)

#define SWAP2(x, y)   SWAPN(0x55555555, 0xAAAAAAAA, 1, x, y)

#define SWAP4(x, y)   SWAPN(0x33333333, 0xCCCCCCCC, 2, x, y)

#define SWAP8(x, y)   SWAPN(0x0F0F0F0F, 0xF0F0F0F0, 4, x, y)

  SWAP2(q[0], q[1]);

  SWAP2(q[2], q[3]);

  SWAP2(q[4], q[5]);

  SWAP2(q[6], q[7]);

  SWAP4(q[0], q[2]);

  SWAP4(q[1], q[3]);

  SWAP4(q[4], q[6]);

  SWAP4(q[5], q[7]);

  SWAP8(q[0], q[4]);

  SWAP8(q[1], q[5]);

  SWAP8(q[2], q[6]);

  SWAP8(q[3], q[7]);

}

static const unsigned char Rcon[] = {

  0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1B, 0x36

};

static uint32_t

sub_word(uint32_t x)

{

  uint32_t q[8];

  int i;

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

    q[i] = x;

  }

  br_aes_ct_ortho(q);

  br_aes_ct_bitslice_Sbox(q);

  br_aes_ct_ortho(q);

  return q[0];

}

/* see inner.h */

unsigned

br_aes_ct_keysched(uint32_t *comp_skey, const void *key, size_t key_len)

{

  unsigned num_rounds;

  int i, j, k, nk, nkf;

  uint32_t tmp;

  uint32_t skey[120];

  switch (key_len) {

  case 16:

    num_rounds = 10;

    break;

  case 24:

    num_rounds = 12;

    break;

  case 32:

    num_rounds = 14;

    break;

  default:

    /* abort(); */

    return 0;

  }

  nk = (int)(key_len >> 2);

  nkf = (int)((num_rounds + 1) << 2);

  tmp = 0;

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

    tmp = br_dec32le((const unsigned char *)key + (i << 2));

    skey[(i << 1) + 0] = tmp;

    skey[(i << 1) + 1] = tmp;

  }

  for (i = nk, j = 0, k = 0; i < nkf; i ++) {

    if (j == 0) {

      tmp = (tmp << 24) | (tmp >> 8);

      tmp = sub_word(tmp) ^ Rcon[k];

    } else if (nk > 6 && j == 4) {

      tmp = sub_word(tmp);

    }

    tmp ^= skey[(i - nk) << 1];

    skey[(i << 1) + 0] = tmp;

    skey[(i << 1) + 1] = tmp;

    if (++ j == nk) {

      j = 0;

      k ++;

    }

  }

  for (i = 0; i < nkf; i += 4) {

    br_aes_ct_ortho(skey + (i << 1));

  }

  for (i = 0, j = 0; i < nkf; i ++, j += 2) {

    comp_skey[i] = (skey[j + 0] & 0x55555555)

      | (skey[j + 1] & 0xAAAAAAAA);

  }

  return num_rounds;

}

/* see inner.h */

void

br_aes_ct_skey_expand(uint32_t *skey,

  unsigned num_rounds, const uint32_t *comp_skey)

{

  unsigned u, v, n;

  n = (num_rounds + 1) << 2;

  for (u = 0, v = 0; u < n; u ++, v += 2) {

    uint32_t x, y;

    x = y = comp_skey[u];

    x &= 0x55555555;

    skey[v + 0] = x | (x << 1);

    y &= 0xAAAAAAAA;

    skey[v + 1] = y | (y >> 1);

  }

}