pkcs1-rsa-sha512.c

   1 /* pkcs1-rsa-sha512.c
   2
   3    PKCS stuff for rsa-sha512.
   4
   5    Copyright (C) 2001, 2003, 2006, 2010 Niels Möller
   6
   7    This file is part of GNU Nettle.
   8
   9    GNU Nettle is free software: you can redistribute it and/or
  10    modify it under the terms of either:
  11
  12      * the GNU Lesser General Public License as published by the Free
  13        Software Foundation; either version 3 of the License, or (at your
  14        option) any later version.
  15
  16    or
  17
  18      * the GNU General Public License as published by the Free
  19        Software Foundation; either version 2 of the License, or (at your
  20        option) any later version.
  21
  22    or both in parallel, as here.
  23
  24    GNU Nettle is distributed in the hope that it will be useful,
  25    but WITHOUT ANY WARRANTY; without even the implied warranty of
  26    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  27    General Public License for more details.
  28
  29    You should have received copies of the GNU General Public License and
  30    the GNU Lesser General Public License along with this program.  If
  31    not, see http://www.gnu.org/licenses/.
  32 */
  33
  34 #if HAVE_CONFIG_H
  35 # include "config.h"
  36 #endif
  37
  38 #include <assert.h>
  39 #include <stdlib.h>
  40 #include <string.h>
  41
  42 #include "rsa.h"
  43
  44 #include "bignum.h"
  45 #include "pkcs1.h"
  46 #include "hogweed-internal.h"
  47
  48 #include "gmp-glue.h"
  49
  50 /* From RFC 3447, Public-Key Cryptography Standards (PKCS) #1: RSA
  51  * Cryptography Specifications Version 2.1.
  52  *
  53  *     id-sha512    OBJECT IDENTIFIER ::=
  54  *       {joint-iso-itu-t(2) country(16) us(840) organization(1)
  55  *         gov(101) csor(3) nistalgorithm(4) hashalgs(2) 3}
  56  */
  57
  58 static const uint8_t
  59 sha512_prefix[] =
  60 {
  61   /* 19 octets prefix, 64 octets hash, total 83 */
  62   0x30,      81, /* SEQUENCE */
  63     0x30,    13, /* SEQUENCE */
  64       0x06,   9, /* OBJECT IDENTIFIER */
  65         0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
  66       0x05,   0, /* NULL */
  67     0x04,    64  /* OCTET STRING */
  68       /* Here comes the raw hash value, 64 octets */
  69 };
  70
  71 int
  72 pkcs1_rsa_sha512_encode(mpz_t m, size_t key_size, struct sha512_ctx *hash)
  73 {
  74   uint8_t *p;
  75   TMP_GMP_DECL(em, uint8_t);
  76
  77   TMP_GMP_ALLOC(em, key_size);
  78
  79   p = _pkcs1_signature_prefix(key_size, em,
  80                               sizeof(sha512_prefix),
  81                               sha512_prefix,
  82                               SHA512_DIGEST_SIZE);
  83   if (p)
  84     {
  85       sha512_digest(hash, SHA512_DIGEST_SIZE, p);
  86       nettle_mpz_set_str_256_u(m, key_size, em);
  87       TMP_GMP_FREE(em);
  88       return 1;
  89     }
  90   else
  91     {
  92       TMP_GMP_FREE(em);
  93       return 0;
  94     }
  95 }
  96
  97 int
  98 pkcs1_rsa_sha512_encode_digest(mpz_t m, size_t key_size, const uint8_t *digest)
  99 {
 100   uint8_t *p;
 101   TMP_GMP_DECL(em, uint8_t);
 102
 103   TMP_GMP_ALLOC(em, key_size);
 104
 105   p = _pkcs1_signature_prefix(key_size, em,
 106                               sizeof(sha512_prefix),
 107                               sha512_prefix,
 108                               SHA512_DIGEST_SIZE);
 109   if (p)
 110     {
 111       memcpy(p, digest, SHA512_DIGEST_SIZE);
 112       nettle_mpz_set_str_256_u(m, key_size, em);
 113       TMP_GMP_FREE(em);
 114       return 1;
 115     }
 116   else
 117     {
 118       TMP_GMP_FREE(em);
 119       return 0;
 120     }
 121 }