|
15
|
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 /* design then PSS depad */ |
|
|
17 int rsa_verify_hash(const unsigned char *sig, unsigned long siglen, |
|
|
18 const unsigned char *msghash, unsigned long msghashlen, |
|
|
19 prng_state *prng, int prng_idx, |
|
|
20 int hash_idx, unsigned long saltlen, |
|
|
21 int *stat, rsa_key *key) |
|
|
22 { |
|
|
23 unsigned long modulus_bitlen, modulus_bytelen, x; |
|
|
24 int err; |
|
|
25 unsigned char *tmpbuf; |
|
|
26 |
|
|
27 _ARGCHK(msghash != NULL); |
|
|
28 _ARGCHK(sig != NULL); |
|
|
29 _ARGCHK(stat != NULL); |
|
|
30 _ARGCHK(key != NULL); |
|
|
31 |
|
|
32 /* valid hash ? */ |
|
|
33 if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) { |
|
|
34 return err; |
|
|
35 } |
|
|
36 |
|
|
37 if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) { |
|
|
38 return err; |
|
|
39 } |
|
|
40 |
|
|
41 /* get modulus len in bits */ |
|
|
42 modulus_bitlen = mp_count_bits(&(key->N)); |
|
|
43 |
|
|
44 /* outlen must be at least the size of the modulus */ |
|
|
45 modulus_bytelen = mp_unsigned_bin_size(&(key->N)); |
|
|
46 if (modulus_bytelen != siglen) { |
|
|
47 return CRYPT_INVALID_PACKET; |
|
|
48 } |
|
|
49 |
|
|
50 /* allocate temp buffer for decoded sig */ |
|
|
51 tmpbuf = XCALLOC(1, modulus_bytelen + 1); |
|
|
52 if (tmpbuf == NULL) { |
|
|
53 return CRYPT_MEM; |
|
|
54 } |
|
|
55 |
|
|
56 /* RSA decode it */ |
|
|
57 x = siglen; |
|
|
58 if ((err = rsa_exptmod(sig, siglen, tmpbuf, &x, PK_PUBLIC, prng, prng_idx, key)) != CRYPT_OK) { |
|
|
59 XFREE(tmpbuf); |
|
|
60 return err; |
|
|
61 } |
|
|
62 |
|
|
63 /* PSS decode it */ |
|
|
64 err = pkcs_1_pss_decode(msghash, msghashlen, tmpbuf, x, saltlen, hash_idx, modulus_bitlen, stat); |
|
|
65 XFREE(tmpbuf); |
|
|
66 return err; |
|
|
67 } |
|
|
68 |
|
|
69 #endif /* MRSA */ |
