4
/* nettle, low-level cryptographics library
6
* Copyright (C) 2013 Niels Möller
8
* The nettle library is free software; you can redistribute it and/or modify
9
* it under the terms of the GNU Lesser General Public License as published by
10
* the Free Software Foundation; either version 2.1 of the License, or (at your
11
* option) any later version.
13
* The nettle library is distributed in the hope that it will be useful, but
14
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
16
* License for more details.
18
* You should have received a copy of the GNU Lesser General Public License
19
* along with the nettle library; see the file COPYING.LIB. If not, write to
20
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
36
umac32_set_key (struct umac32_ctx *ctx, const uint8_t *key)
38
_umac_set_key (ctx->l1_key, ctx->l2_key, ctx->l3_key1, ctx->l3_key2,
39
&ctx->pdf_key, key, 1);
42
memset (ctx->nonce, 0, sizeof(ctx->nonce));
44
ctx->nonce_length = sizeof(ctx->nonce);
46
/* Initialize buffer */
47
ctx->count = ctx->index = 0;
51
umac32_set_nonce (struct umac32_ctx *ctx,
52
unsigned nonce_length, const uint8_t *nonce)
54
assert (nonce_length > 0);
55
assert (nonce_length <= AES_BLOCK_SIZE);
57
memcpy (ctx->nonce, nonce, nonce_length);
58
memset (ctx->nonce + nonce_length, 0, AES_BLOCK_SIZE - nonce_length);
60
ctx->nonce_low = ctx->nonce[nonce_length - 1] & 3;
61
ctx->nonce[nonce_length - 1] &= ~3;
62
ctx->nonce_length = nonce_length;
65
#define UMAC32_BLOCK(ctx, block) do { \
67
= _umac_nh (ctx->l1_key, UMAC_DATA_SIZE, block) \
68
+ 8*UMAC_DATA_SIZE ; \
69
_umac_l2 (ctx->l2_key, ctx->l2_state, 1, ctx->count++, &__umac32_y); \
73
umac32_update (struct umac32_ctx *ctx,
74
unsigned length, const uint8_t *data)
76
MD_UPDATE (ctx, length, data, UMAC32_BLOCK, (void)0);
81
umac32_digest (struct umac32_ctx *ctx,
82
unsigned length, uint8_t *digest)
89
if (ctx->index > 0 || ctx->count == 0)
91
/* Zero pad to multiple of 32 */
93
unsigned pad = (ctx->index > 0) ? 31 & - ctx->index : 32;
94
memset (ctx->block + ctx->index, 0, pad);
96
y = _umac_nh (ctx->l1_key, ctx->index + pad, ctx->block)
98
_umac_l2 (ctx->l2_key, ctx->l2_state, 1, ctx->count++, &y);
100
assert (ctx->count > 0);
101
if ( !(ctx->nonce_low & _UMAC_NONCE_CACHED))
103
aes_encrypt (&ctx->pdf_key, AES_BLOCK_SIZE,
104
(uint8_t *) ctx->pad_cache, ctx->nonce);
105
ctx->nonce_low |= _UMAC_NONCE_CACHED;
108
pad = ctx->pad_cache[ctx->nonce_low & 3];
110
/* Increment nonce */
112
if ( !(ctx->nonce_low & 3))
114
unsigned i = ctx->nonce_length - 1;
119
if (ctx->nonce[i] == 0 && i > 0)
120
INCREMENT (i, ctx->nonce);
123
_umac_l2_final (ctx->l2_key, ctx->l2_state, 1, ctx->count);
124
pad ^= ctx->l3_key2[0] ^ _umac_l3 (ctx->l3_key1, ctx->l2_state);
125
memcpy (digest, &pad, length);
128
ctx->count = ctx->index = 0;