/*
* 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);
}
}