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/* pkcs1-rsa-md5.c
*
* PKCS stuff for rsa-md5.
*/
/* nettle, low-level cryptographics library
*
* Copyright (C) 2001, 2003 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., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*/
#if HAVE_CONFIG_H
# include "config.h"
#endif
#if WITH_PUBLIC_KEY
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include "rsa.h"
#include "bignum.h"
#include "pkcs1.h"
#include "nettle-internal.h"
/* From pkcs-1v2
*
* md5 OBJECT IDENTIFIER ::=
* {iso(1) member-body(2) US(840) rsadsi(113549) digestAlgorithm(2) 5}
*
* The parameters part of the algorithm identifier is NULL:
*
* md5Identifier ::= AlgorithmIdentifier {md5, NULL}
*/
static const uint8_t
md5_prefix[] =
{
/* 18 octets prefix, 16 octets hash, 34 total. */
0x30, 32, /* SEQUENCE */
0x30, 12, /* SEQUENCE */
0x06, 8, /* OBJECT IDENTIFIER */
0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05,
0x05, 0, /* NULL */
0x04, 16 /* OCTET STRING */
/* Here comes the raw hash value */
};
void
pkcs1_rsa_md5_encode(mpz_t m, unsigned length, struct md5_ctx *hash)
{
TMP_DECL(em, uint8_t, NETTLE_MAX_BIGNUM_BITS / 8);
TMP_ALLOC(em, length);
assert(length >= MD5_DIGEST_SIZE);
pkcs1_signature_prefix(length - MD5_DIGEST_SIZE, em,
sizeof(md5_prefix),
md5_prefix);
md5_digest(hash, MD5_DIGEST_SIZE, em + length - MD5_DIGEST_SIZE);
nettle_mpz_set_str_256_u(m, length, em);
}
void
pkcs1_rsa_md5_encode_digest(mpz_t m, unsigned length, const uint8_t *digest)
{
TMP_DECL(em, uint8_t, NETTLE_MAX_BIGNUM_BITS / 8);
TMP_ALLOC(em, length);
assert(length >= MD5_DIGEST_SIZE);
pkcs1_signature_prefix(length - MD5_DIGEST_SIZE, em,
sizeof(md5_prefix),
md5_prefix);
memcpy(em + length - MD5_DIGEST_SIZE, digest, MD5_DIGEST_SIZE);
nettle_mpz_set_str_256_u(m, length, em);
}
#endif /* WITH_PUBLIC_KEY */
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