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comparison src/pk/pkcs1/pkcs_1_mgf1.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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children 39d5d58461d6
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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 pkcs_1_mgf1.c
15 The Mask Generation Function (MGF1) for PKCS #1, Tom St Denis
16 */
17
18 #ifdef PKCS_1
19
20 /**
21 Perform PKCS #1 MGF1 (internal)
22 @param seed The seed for MGF1
23 @param seedlen The length of the seed
24 @param hash_idx The index of the hash desired
25 @param mask [out] The destination
26 @param masklen The length of the mask desired
27 @return CRYPT_OK if successful
28 */
29 int pkcs_1_mgf1(const unsigned char *seed, unsigned long seedlen,
30 int hash_idx,
31 unsigned char *mask, unsigned long masklen)
32 {
33 unsigned long hLen, x;
34 ulong32 counter;
35 int err;
36 hash_state *md;
37 unsigned char *buf;
38
39 LTC_ARGCHK(seed != NULL);
40 LTC_ARGCHK(mask != NULL);
41
42 /* ensure valid hash */
43 if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) {
44 return err;
45 }
46
47 /* get hash output size */
48 hLen = hash_descriptor[hash_idx].hashsize;
49
50 /* allocate memory */
51 md = XMALLOC(sizeof(hash_state));
52 buf = XMALLOC(hLen);
53 if (md == NULL || buf == NULL) {
54 if (md != NULL) {
55 XFREE(md);
56 }
57 if (buf != NULL) {
58 XFREE(buf);
59 }
60 return CRYPT_MEM;
61 }
62
63 /* start counter */
64 counter = 0;
65
66 while (masklen > 0) {
67 /* handle counter */
68 STORE32H(counter, buf);
69 ++counter;
70
71 /* get hash of seed || counter */
72 if ((err = hash_descriptor[hash_idx].init(md)) != CRYPT_OK) {
73 goto LBL_ERR;
74 }
75 if ((err = hash_descriptor[hash_idx].process(md, seed, seedlen)) != CRYPT_OK) {
76 goto LBL_ERR;
77 }
78 if ((err = hash_descriptor[hash_idx].process(md, buf, 4)) != CRYPT_OK) {
79 goto LBL_ERR;
80 }
81 if ((err = hash_descriptor[hash_idx].done(md, buf)) != CRYPT_OK) {
82 goto LBL_ERR;
83 }
84
85 /* store it */
86 for (x = 0; x < hLen && masklen > 0; x++, masklen--) {
87 *mask++ = buf[x];
88 }
89 }
90
91 err = CRYPT_OK;
92 LBL_ERR:
93 #ifdef LTC_CLEAN_STACK
94 zeromem(buf, hLen);
95 zeromem(md, sizeof(hash_state));
96 #endif
97
98 XFREE(buf);
99 XFREE(md);
100
101 return err;
102 }
103
104 #endif /* PKCS_1 */