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/* pkcs1-rsa-sha256.c
*
* PKCS stuff for rsa-sha256.
*/
/* nettle, low-level cryptographics library
*
* Copyright (C) 2001, 2003, 2006 Niels Möller
*
* 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., 51 Franklin Street, Fifth Floor, Boston,
* MA 02111-1301, USA.
*/
#if HAVE_CONFIG_H
# include "config.h"
#endif
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include "rsa.h"
#include "bignum.h"
#include "pkcs1.h"
#include "nettle-internal.h"
/* From RFC 3447, Public-Key Cryptography Standards (PKCS) #1: RSA
* Cryptography Specifications Version 2.1.
*
* id-sha256 OBJECT IDENTIFIER ::=
* {joint-iso-itu-t(2) country(16) us(840) organization(1)
* gov(101) csor(3) nistalgorithm(4) hashalgs(2) 1}
*/
static const uint8_t
sha256_prefix[] =
{
/* 19 octets prefix, 32 octets hash, total 51 */
0x30, 49, /* SEQUENCE */
0x30, 13, /* SEQUENCE */
0x06, 9, /* OBJECT IDENTIFIER */
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
0x05, 0, /* NULL */
0x04, 32 /* OCTET STRING */
/* Here comes the raw hash value */
};
int
pkcs1_rsa_sha256_encode(mpz_t m, size_t key_size, struct sha256_ctx *hash)
{
uint8_t *p;
TMP_DECL(em, uint8_t, NETTLE_MAX_BIGNUM_SIZE);
TMP_ALLOC(em, key_size);
p = _pkcs1_signature_prefix(key_size, em,
sizeof(sha256_prefix),
sha256_prefix,
SHA256_DIGEST_SIZE);
if (p)
{
sha256_digest(hash, SHA256_DIGEST_SIZE, p);
nettle_mpz_set_str_256_u(m, key_size, em);
return 1;
}
else
return 0;
}
int
pkcs1_rsa_sha256_encode_digest(mpz_t m, size_t key_size, const uint8_t *digest)
{
uint8_t *p;
TMP_DECL(em, uint8_t, NETTLE_MAX_BIGNUM_SIZE);
TMP_ALLOC(em, key_size);
p = _pkcs1_signature_prefix(key_size, em,
sizeof(sha256_prefix),
sha256_prefix,
SHA256_DIGEST_SIZE);
if (p)
{
memcpy(p, digest, SHA256_DIGEST_SIZE);
nettle_mpz_set_str_256_u(m, key_size, em);
return 1;
}
else
return 0;
}
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