static void inv_mix_columns(uint8_t *input) {
static uint8_t mult9[16];
static uint8_t mult11[16];
static uint8_t mult13[16];
static uint8_t mult14[16];
int i;
for (i = 0; i < 16; i++) {
mult9[i] = gf_mult(9, input[i]);
mult11[i] = gf_mult(11, input[i]);
mult13[i] = gf_mult(13, input[i]);
mult14[i] = gf_mult(14, input[i]);
}
for (i = 0; i < 4;i++) {
input[i * 4] = mult14[i * 4] ^ mult11[i * 4 + 1] ^ mult13[i * 4 + 2] ^ mult9[i * 4 + 3];
input[i * 4 + 1] = mult9[i * 4] ^ mult14[i * 4 + 1] ^ mult11[i * 4 + 2] ^ mult13[i * 4 + 3];
input[i * 4 + 2] = mult13[i * 4] ^ mult9[i * 4 + 1] ^ mult14[i * 4 + 2] ^ mult11[i * 4 + 3];
input[i * 4 + 3] = mult11[i * 4] ^ mult13[i * 4 + 1] ^ mult9[i * 4 + 2] ^ mult14[i * 4 + 3];
}
}
static void mix_bytes (uint8_t block[8][16]) {
uint8_t temp[8][16];
memset (temp, 0, sizeof (temp));
for (uint_fast8_t i = 0; i < 8; i++) {
for (uint_fast8_t j = 0; j < 16; j++) {
for (uint_fast8_t k = 0; k < 8; k++) {
temp[i][j] ^= gf_mult (diffusion_matrix[i][k], block[k][j]);
}
}
}
memcpy (block, temp, sizeof (temp));
}
static void ghash(const u8 *h, const u8 *x, size_t xlen, u8 *y)
{
size_t m, i;
const u8 *xpos = x;
u8 tmp[16];
m = xlen / 16;
for (i = 0; i < m; i++) {
/* Y_i = (Y^(i-1) XOR X_i) dot H */
xor_block(y, xpos);
xpos += 16;
/* dot operation:
* multiplication operation for binary Galois (finite) field of
* 2^128 elements */
gf_mult(y, h, tmp);
os_memcpy(y, tmp, 16);
}
if (x + xlen > xpos) {
/* Add zero padded last block */
size_t last = x + xlen - xpos;
os_memcpy(tmp, xpos, last);
os_memset(tmp + last, 0, sizeof(tmp) - last);
/* Y_i = (Y^(i-1) XOR X_i) dot H */
xor_block(y, tmp);
/* dot operation:
* multiplication operation for binary Galois (finite) field of
* 2^128 elements */
gf_mult(y, h, tmp);
os_memcpy(y, tmp, 16);
}
/* Return Y_m */
}
void test_distributive_law() {
suite("distributive law");
SOME3( test(gf_mult(gf_add(a,b), c) == gf_add(gf_mult(a,c), gf_mult(b,c))); )
}
void test_mult_zeroes() {
suite("multiplication by zero is zero");
ALL1( test(gf_mult(a,0) == 0); )
}
void test_mult_associates() {
suite("multiplication associates");
SOME3( test(gf_mult(gf_mult(a,b), c) == gf_mult(a, gf_mult(b,c))); )
}
void test_mult_commutes() {
suite("multiplication commutes");
ALL2( test(gf_mult(a,b) == gf_mult(b,a)); )
}
