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comparison rsa_sign_hash.c @ 15:6362d3854bb4 libtomcrypt-orig

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0.96 release of LibTomCrypt
author Matt Johnston <matt@ucc.asn.au>
date Tue, 15 Jun 2004 14:07:21 +0000
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children 5d99163f7e32
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3:7faae8f46238 15:6362d3854bb4
1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 *
9 * Tom St Denis, [email protected], http://libtomcrypt.org
10 */
11
12 #include "mycrypt.h"
13
14 #ifdef MRSA
15
16 /* PSS pad then sign */
17 int rsa_sign_hash(const unsigned char *msghash, unsigned long msghashlen,
18 unsigned char *sig, unsigned long *siglen,
19 prng_state *prng, int prng_idx,
20 int hash_idx, unsigned long saltlen,
21 rsa_key *key)
22 {
23 unsigned long modulus_bitlen, modulus_bytelen, x;
24 int err;
25
26 _ARGCHK(msghash != NULL);
27 _ARGCHK(sig != NULL);
28 _ARGCHK(siglen != NULL);
29 _ARGCHK(key != NULL);
30
31 /* valid prng and hash ? */
32 if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) {
33 return err;
34 }
35 if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) {
36 return err;
37 }
38
39 /* get modulus len in bits */
40 modulus_bitlen = mp_count_bits(&(key->N));
41
42 /* outlen must be at least the size of the modulus */
43 modulus_bytelen = mp_unsigned_bin_size(&(key->N));
44 if (modulus_bytelen > *siglen) {
45 return CRYPT_BUFFER_OVERFLOW;
46 }
47
48 /* PSS pad the key */
49 x = *siglen;
50 if ((err = pkcs_1_pss_encode(msghash, msghashlen, saltlen, prng, prng_idx,
51 hash_idx, modulus_bitlen, sig, &x)) != CRYPT_OK) {
52 return err;
53 }
54
55 /* RSA encode it */
56 return rsa_exptmod(sig, x, sig, siglen, PK_PRIVATE, prng, prng_idx, key);
57 }
58
59 #endif /* MRSA */