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comparison src/pk/rsa/rsa_v15_sign_hash.c @ 191:1c15b283127b libtomcrypt-orig

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Import of libtomcrypt 1.02 with manual path rename rearrangement etc
author Matt Johnston <matt@ucc.asn.au>
date Fri, 06 May 2005 13:23:02 +0000
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143:5d99163f7e32 191:1c15b283127b
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 #include "tomcrypt.h"
12
13 /**
14 @file rsa_v15_sign_hash.c
15 RSA PKCS v1.5 Signature, Tom St Denis
16 */
17
18 #ifdef MRSA
19
20 /**
21 PKCS #1 v1.5 pad then sign
22 @param in The hash to sign
23 @param inlen The length of the message hash (octets)
24 @param out [out] The signature
25 @param siglen [in/out] The max size and resulting size of the signature
26 @param hash_idx The index of the hash desired
27 @param key The private RSA key to perform the signature with
28 @return CRYPT_OK if successful
29 */
30 int rsa_v15_sign_hash(const unsigned char *in, unsigned long inlen,
31 unsigned char *out, unsigned long *siglen,
32 int hash_idx, rsa_key *key)
33 {
34 unsigned long modulus_bitlen, modulus_bytelen, x;
35 int err;
36
37 LTC_ARGCHK(in != NULL);
38 LTC_ARGCHK(out != NULL);
39 LTC_ARGCHK(siglen != NULL);
40 LTC_ARGCHK(key != NULL);
41
42 /* valid hash ? */
43 if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) {
44 return err;
45 }
46
47 /* get modulus len in bits */
48 modulus_bitlen = mp_count_bits(&(key->N));
49
50 /* outlen must be at least the size of the modulus */
51 modulus_bytelen = mp_unsigned_bin_size(&(key->N));
52 if (modulus_bytelen > *siglen) {
53 return CRYPT_BUFFER_OVERFLOW;
54 }
55
56 /* PKCS #1 v1.5 pad the key */
57 x = *siglen;
58 if ((err = pkcs_1_v15_sa_encode(in, inlen, hash_idx, modulus_bitlen, out, &x)) != CRYPT_OK) {
59 return err;
60 }
61
62 /* RSA encode it */
63 return rsa_exptmod(out, x, out, siglen, PK_PRIVATE, key);
64 }
65
66 #endif