void
umac32_digest (struct umac32_ctx *ctx,
size_t length, uint8_t *digest)
{
uint32_t pad;
assert (length > 0);
assert (length <= 4);
if (ctx->index > 0 || ctx->count == 0)
{
/* Zero pad to multiple of 32 */
uint64_t y;
unsigned pad = (ctx->index > 0) ? 31 & - ctx->index : 32;
memset (ctx->block + ctx->index, 0, pad);
y = _umac_nh (ctx->l1_key, ctx->index + pad, ctx->block)
+ 8 * ctx->index;
_umac_l2 (ctx->l2_key, ctx->l2_state, 1, ctx->count++, &y);
}
assert (ctx->count > 0);
if ( !(ctx->nonce_low & _UMAC_NONCE_CACHED))
{
aes128_encrypt (&ctx->pdf_key, AES_BLOCK_SIZE,
(uint8_t *) ctx->pad_cache, ctx->nonce);
ctx->nonce_low |= _UMAC_NONCE_CACHED;
}
pad = ctx->pad_cache[ctx->nonce_low & 3];
/* Increment nonce */
ctx->nonce_low++;
if ( !(ctx->nonce_low & 3))
{
unsigned i = ctx->nonce_length - 1;
ctx->nonce_low = 0;
ctx->nonce[i] += 4;
if (ctx->nonce[i] == 0 && i > 0)
INCREMENT (i, ctx->nonce);
}
_umac_l2_final (ctx->l2_key, ctx->l2_state, 1, ctx->count);
pad ^= ctx->l3_key2[0] ^ _umac_l3 (ctx->l3_key1, ctx->l2_state);
memcpy (digest, &pad, length);
/* Reinitialize */
ctx->count = ctx->index = 0;
}
void
umac96_digest (struct umac96_ctx *ctx,
size_t length, uint8_t *digest)
{
uint32_t tag[4];
unsigned i;
assert (length > 0);
assert (length <= 12);
if (ctx->index > 0 || ctx->count == 0)
{
/* Zero pad to multiple of 32 */
uint64_t y[3];
unsigned pad = (ctx->index > 0) ? 31 & - ctx->index : 32;
memset (ctx->block + ctx->index, 0, pad);
_umac_nh_n (y, 3, ctx->l1_key, ctx->index + pad, ctx->block);
y[0] += 8 * ctx->index;
y[1] += 8 * ctx->index;
y[2] += 8 * ctx->index;
_umac_l2 (ctx->l2_key, ctx->l2_state, 3, ctx->count++, y);
}
assert (ctx->count > 0);
aes128_encrypt (&ctx->pdf_key, AES_BLOCK_SIZE,
(uint8_t *) tag, ctx->nonce);
INCREMENT (ctx->nonce_length, ctx->nonce);
_umac_l2_final (ctx->l2_key, ctx->l2_state, 3, ctx->count);
for (i = 0; i < 3; i++)
tag[i] ^= ctx->l3_key2[i] ^ _umac_l3 (ctx->l3_key1 + 8*i,
ctx->l2_state + 2*i);
memcpy (digest, tag, length);
/* Reinitialize */
ctx->count = ctx->index = 0;
}
