pkcs1-rsa-sha1.c 2.43 KB
Newer Older
Niels Möller's avatar
Niels Möller committed
1
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
/* pkcs1-rsa-md5.c
 *
 * PKCS stuff for rsa-md5.
 */

/* nettle, low-level cryptographics library
 *
 * Copyright (C) 2001, 2003 Niels Mller
 *  
 * The nettle library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at your
 * option) any later version.
 * 
 * The nettle library 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 Lesser General Public
 * License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with the nettle library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

#if HAVE_CONFIG_H
27
# include "config.h"
Niels Möller's avatar
Niels Möller committed
28
29
30
31
#endif

#if WITH_PUBLIC_KEY

32
33
34
35
#include <assert.h>
#include <stdlib.h>
#include <string.h>

Niels Möller's avatar
Niels Möller committed
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
#include "rsa.h"

#include "bignum.h"
#include "pkcs1.h"

/* From pkcs-1v2
 *
 *   id-sha1 OBJECT IDENTIFIER ::=
 *     {iso(1) identified-organization(3) oiw(14) secsig(3)
 *   	 algorithms(2) 26}
 *   
 *   The default hash function is SHA-1: 
 *   sha1Identifier ::= AlgorithmIdentifier {id-sha1, NULL}
 */

static const uint8_t
sha1_prefix[] =
{
  /* 15 octets prefix, 20 octets hash, total 35 */
  0x30,       33, /* SEQUENCE */
    0x30,      9, /* SEQUENCE */
      0x06,    5, /* OBJECT IDENTIFIER */
  	  0x2b, 0x0e, 0x03, 0x02, 0x1a,
      0x05,    0, /* NULL */
    0x04,     20  /* OCTET STRING */
      /* Here comes the raw hash value */
};

void
pkcs1_rsa_sha1_encode(mpz_t m, unsigned length, struct sha1_ctx *hash)
{
  uint8_t *em = alloca(length);

  assert(length >= SHA1_DIGEST_SIZE);
  pkcs1_signature_prefix(length - SHA1_DIGEST_SIZE, em,
			 sizeof(sha1_prefix),
			 sha1_prefix);
  
  sha1_digest(hash, SHA1_DIGEST_SIZE, em + length - SHA1_DIGEST_SIZE);
  nettle_mpz_set_str_256_u(m, length, em);
}

void
pkcs1_rsa_sha1_encode_digest(mpz_t m, unsigned length, const uint8_t *digest)
{
  uint8_t *em = alloca(length);

  assert(length >= SHA1_DIGEST_SIZE);
  pkcs1_signature_prefix(length - SHA1_DIGEST_SIZE, em,
			 sizeof(sha1_prefix),
			 sha1_prefix);

  memcpy(em + length - SHA1_DIGEST_SIZE, digest, SHA1_DIGEST_SIZE);
  nettle_mpz_set_str_256_u(m, length, em);
}

#endif /* WITH_PUBLIC_KEY */