release/src/router/nettle/pkcs1-rsa-sha1.c

   1 /* pkcs1-rsa-sha1.c
   2  *
   3  * PKCS stuff for rsa-sha1.
   4  */
   5
   6 /* nettle, low-level cryptographics library
   7  *
   8  * Copyright (C) 2001, 2003 Niels Möller
   9  *
  10  * The nettle library is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU Lesser General Public License as published by
  12  * the Free Software Foundation; either version 2.1 of the License, or (at your
  13  * option) any later version.
  14  *
  15  * The nettle library is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  17  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  18  * License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with the nettle library; see the file COPYING.LIB.  If not, write to
  22  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  23  * MA 02111-1301, USA.
  24  */
  25
  26 #if HAVE_CONFIG_H
  27 # include "config.h"
  28 #endif
  29
  30 #include <assert.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33
  34 #include "rsa.h"
  35
  36 #include "bignum.h"
  37 #include "pkcs1.h"
  38
  39 #include "nettle-internal.h"
  40
  41 /* From pkcs-1v2
  42  *
  43  *   id-sha1 OBJECT IDENTIFIER ::=
  44  *     {iso(1) identified-organization(3) oiw(14) secsig(3)
  45  *       algorithms(2) 26}
  46  *
  47  *   The default hash function is SHA-1:
  48  *   sha1Identifier ::= AlgorithmIdentifier {id-sha1, NULL}
  49  */
  50
  51 static const uint8_t
  52 sha1_prefix[] =
  53 {
  54   /* 15 octets prefix, 20 octets hash, total 35 */
  55   0x30,       33, /* SEQUENCE */
  56     0x30,      9, /* SEQUENCE */
  57       0x06,    5, /* OBJECT IDENTIFIER */
  58           0x2b, 0x0e, 0x03, 0x02, 0x1a,
  59       0x05,    0, /* NULL */
  60     0x04,     20  /* OCTET STRING */
  61       /* Here comes the raw hash value */
  62 };
  63
  64 int
  65 pkcs1_rsa_sha1_encode(mpz_t m, unsigned key_size, struct sha1_ctx *hash)
  66 {
  67   uint8_t *p;
  68   TMP_DECL(em, uint8_t, NETTLE_MAX_BIGNUM_SIZE);
  69   TMP_ALLOC(em, key_size);
  70
  71   p = _pkcs1_signature_prefix(key_size, em,
  72                               sizeof(sha1_prefix),
  73                               sha1_prefix,
  74                               SHA1_DIGEST_SIZE);
  75   if (p)
  76     {
  77       sha1_digest(hash, SHA1_DIGEST_SIZE, p);
  78       nettle_mpz_set_str_256_u(m, key_size, em);
  79       return 1;
  80     }
  81   else
  82     return 0;
  83 }
  84
  85 int
  86 pkcs1_rsa_sha1_encode_digest(mpz_t m, unsigned key_size, const uint8_t *digest)
  87 {
  88   uint8_t *p;
  89   TMP_DECL(em, uint8_t, NETTLE_MAX_BIGNUM_SIZE);
  90   TMP_ALLOC(em, key_size);
  91
  92   p = _pkcs1_signature_prefix(key_size, em,
  93                               sizeof(sha1_prefix),
  94                               sha1_prefix,
  95                               SHA1_DIGEST_SIZE);
  96   if (p)
  97     {
  98       memcpy(p, digest, SHA1_DIGEST_SIZE);
  99       nettle_mpz_set_str_256_u(m, key_size, em);
 100       return 1;
 101     }
 102   else
 103     return 0;
 104 }