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/*
* 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"
#define S br_aes_S
static void
add_round_key(unsigned *state, const uint32_t *skeys)
{
int i;
for (i = 0; i < 16; i += 4) {
uint32_t k;
k = *skeys ++;
state[i + 0] ^= (unsigned)(k >> 24);
state[i + 1] ^= (unsigned)(k >> 16) & 0xFF;
state[i + 2] ^= (unsigned)(k >> 8) & 0xFF;
state[i + 3] ^= (unsigned)k & 0xFF;
}
}
static void
sub_bytes(unsigned *state)
{
int i;
for (i = 0; i < 16; i ++) {
state[i] = S[state[i]];
}
}
static void
shift_rows(unsigned *state)
{
unsigned tmp;
tmp = state[1];
state[1] = state[5];
state[5] = state[9];
state[9] = state[13];
state[13] = tmp;
tmp = state[2];
state[2] = state[10];
state[10] = tmp;
tmp = state[6];
state[6] = state[14];
state[14] = tmp;
tmp = state[15];
state[15] = state[11];
state[11] = state[7];
state[7] = state[3];
state[3] = tmp;
}
static void
mix_columns(unsigned *state)
{
int i;
for (i = 0; i < 16; i += 4) {
unsigned s0, s1, s2, s3;
unsigned t0, t1, t2, t3;
s0 = state[i + 0];
s1 = state[i + 1];
s2 = state[i + 2];
s3 = state[i + 3];
t0 = (s0 << 1) ^ s1 ^ (s1 << 1) ^ s2 ^ s3;
t1 = s0 ^ (s1 << 1) ^ s2 ^ (s2 << 1) ^ s3;
t2 = s0 ^ s1 ^ (s2 << 1) ^ s3 ^ (s3 << 1);
t3 = s0 ^ (s0 << 1) ^ s1 ^ s2 ^ (s3 << 1);
state[i + 0] = t0 ^ ((unsigned)(-(int)(t0 >> 8)) & 0x11B);
state[i + 1] = t1 ^ ((unsigned)(-(int)(t1 >> 8)) & 0x11B);
state[i + 2] = t2 ^ ((unsigned)(-(int)(t2 >> 8)) & 0x11B);
state[i + 3] = t3 ^ ((unsigned)(-(int)(t3 >> 8)) & 0x11B);
}
}
/* see inner.h */
void
br_aes_small_encrypt(unsigned num_rounds, const uint32_t *skey, void *data)
{
unsigned char *buf;
unsigned state[16];
unsigned u;
buf = data;
for (u = 0; u < 16; u ++) {
state[u] = buf[u];
}
add_round_key(state, skey);
for (u = 1; u < num_rounds; u ++) {
sub_bytes(state);
shift_rows(state);
mix_columns(state);
add_round_key(state, skey + (u << 2));
}
sub_bytes(state);
shift_rows(state);
add_round_key(state, skey + (num_rounds << 2));
for (u = 0; u < 16; u ++) {
buf[u] = state[u];
}
}
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