umac128.c 3.4 KB
Newer Older
Niels Möller's avatar
Niels Möller committed
1
/* umac128.c
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

   Copyright (C) 2013 Niels Möller

   This file is part of GNU Nettle.

   GNU Nettle is free software: you can redistribute it and/or
   modify it under the terms of either:

     * the GNU Lesser General Public License as published by the Free
       Software Foundation; either version 3 of the License, or (at your
       option) any later version.

   or

     * the GNU General Public License as published by the Free
       Software Foundation; either version 2 of the License, or (at your
       option) any later version.

   or both in parallel, as here.

   GNU Nettle is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received copies of the GNU General Public License and
   the GNU Lesser General Public License along with this program.  If
   not, see http://www.gnu.org/licenses/.
*/
Niels Möller's avatar
Niels Möller committed
31 32 33 34 35 36 37 38 39

#if HAVE_CONFIG_H
# include "config.h"
#endif

#include <assert.h>
#include <string.h>

#include "umac.h"
40
#include "umac-internal.h"
Niels Möller's avatar
Niels Möller committed
41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59

#include "macros.h"

void
umac128_set_key (struct umac128_ctx *ctx, const uint8_t *key)
{
  _umac_set_key (ctx->l1_key, ctx->l2_key, ctx->l3_key1, ctx->l3_key2,
		 &ctx->pdf_key, key, 4);

  /* Clear nonce */
  memset (ctx->nonce, 0, sizeof(ctx->nonce));
  ctx->nonce_length = sizeof(ctx->nonce);

  /* Initialize buffer */
  ctx->count = ctx->index = 0;
}

void
umac128_set_nonce (struct umac128_ctx *ctx,
60
		   size_t nonce_length, const uint8_t *nonce)
Niels Möller's avatar
Niels Möller committed
61 62 63 64 65 66 67 68 69 70 71 72
{
  assert (nonce_length > 0);
  assert (nonce_length <= AES_BLOCK_SIZE);

  memcpy (ctx->nonce, nonce, nonce_length);
  memset (ctx->nonce + nonce_length, 0, AES_BLOCK_SIZE - nonce_length);

  ctx->nonce_length = nonce_length;
}

#define UMAC128_BLOCK(ctx, block) do {					\
    uint64_t __umac128_y[4];						\
73 74 75 76 77
    _umac_nh_n (__umac128_y, 4, ctx->l1_key, UMAC_BLOCK_SIZE, block);	\
    __umac128_y[0] += 8*UMAC_BLOCK_SIZE;				\
    __umac128_y[1] += 8*UMAC_BLOCK_SIZE;				\
    __umac128_y[2] += 8*UMAC_BLOCK_SIZE;				\
    __umac128_y[3] += 8*UMAC_BLOCK_SIZE;				\
78
    _umac_l2 (ctx->l2_key, ctx->l2_state, 4, ctx->count++, __umac128_y); \
Niels Möller's avatar
Niels Möller committed
79 80 81 82
  } while (0)

void
umac128_update (struct umac128_ctx *ctx,
83
		size_t length, const uint8_t *data)
Niels Möller's avatar
Niels Möller committed
84 85 86 87 88 89 90
{
  MD_UPDATE (ctx, length, data, UMAC128_BLOCK, (void)0);
}


void
umac128_digest (struct umac128_ctx *ctx,
91
		size_t length, uint8_t *digest)
Niels Möller's avatar
Niels Möller committed
92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110
{
  uint32_t tag[4];
  unsigned i;

  assert (length > 0);
  assert (length <= 16);

  if (ctx->index > 0 || ctx->count == 0)
    {
      /* Zero pad to multiple of 32 */
      uint64_t y[4];
      unsigned pad = (ctx->index > 0) ? 31 & - ctx->index : 32;
      memset (ctx->block + ctx->index, 0, pad);

      _umac_nh_n (y, 4, ctx->l1_key, ctx->index + pad, ctx->block);
      y[0] += 8 * ctx->index;
      y[1] += 8 * ctx->index;
      y[2] += 8 * ctx->index;
      y[3] += 8 * ctx->index;
111
      _umac_l2 (ctx->l2_key, ctx->l2_state, 4, ctx->count++, y);
Niels Möller's avatar
Niels Möller committed
112 113 114
    }
  assert (ctx->count > 0);

115 116
  aes128_encrypt (&ctx->pdf_key, AES_BLOCK_SIZE,
		  (uint8_t *) tag, ctx->nonce);
Niels Möller's avatar
Niels Möller committed
117

Niels Möller's avatar
Niels Möller committed
118
  INCREMENT (ctx->nonce_length, ctx->nonce);
Niels Möller's avatar
Niels Möller committed
119

120
  _umac_l2_final (ctx->l2_key, ctx->l2_state, 4, ctx->count);
Niels Möller's avatar
Niels Möller committed
121
  for (i = 0; i < 4; i++)
122 123
    tag[i] ^= ctx->l3_key2[i] ^ _umac_l3 (ctx->l3_key1 + 8*i,
					  ctx->l2_state + 2*i);
Niels Möller's avatar
Niels Möller committed
124 125 126 127 128 129

  memcpy (digest, tag, length);

  /* Reinitialize */
  ctx->count = ctx->index = 0;
}