inline block
garble_random_block(void)
{
block out;
uint64_t *val;
int i;
out = garble_zero_block();
val = (uint64_t *) &out;
val[0] = current_rand_index++;
out = _mm_xor_si128(out, rand_aes_key.rd_key[0]);
for (i = 1; i < 10; ++i)
out = _mm_aesenc_si128(out, rand_aes_key.rd_key[i]);
return _mm_aesenclast_si128(out, rand_aes_key.rd_key[i]);
}
block
garble_seed(block *seed)
{
block cur_seed;
current_rand_index = 0;
if (seed) {
cur_seed = *seed;
} else {
if (RAND_bytes((unsigned char *) &cur_seed, 16) == 0) {
fprintf(stderr, "** unable to seed securely\n");
return garble_zero_block();
}
}
AES_set_encrypt_key(cur_seed, &rand_aes_key);
return cur_seed;
}
static int
computeOutputs(const OutputInstructions *ois, int *output,
block **computed_outputmap)
{
assert(output && "output's memory should be allocated");
for (uint16_t i = 0; i < ois->size; ++i) {
AES_KEY key;
block out[2], b_zero, b_one;
OutputInstruction *oi = &ois->output_instruction[i];
// decrypt using comp_block as key
block comp_block = computed_outputmap[oi->gc_id][oi->wire_id];
/* XXX: huh? why does calling AES_set_decrypt_key not work!? */
/* AES_set_decrypt_key(comp_block, &key); */
{
AES_KEY temp_key;
AES_set_encrypt_key(comp_block, &temp_key);
AES_set_decrypt_key_fast(&key, &temp_key);
}
out[0] = oi->labels[0];
out[1] = oi->labels[1];
AES_ecb_decrypt_blks(out, 2, &key);
b_zero = garble_zero_block();
b_one = garble_make_block((uint64_t) 0, (uint64_t) 1); // 000...00001
if (garble_equal(out[0], b_zero) || garble_equal(out[1], b_zero)) {
output[i] = 0;
} else if (garble_equal(out[0], b_one) || garble_equal(out[1], b_one)) {
output[i] = 1;
} else {
fprintf(stderr, "Could not compute output[%d] from (gc_id: %d, wire_id: %d)\n",
i, oi->gc_id, oi->wire_id);
/* assert(false); */
return FAILURE;
}
}
return SUCCESS;
}