1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis */
2 /* SPDX-License-Identifier: Unlicense */
3 #include "tomcrypt_private.h"
4
5
6 #ifdef LTC_MDSA
7
8 /**
9 Import DSA's p, q & g from dsaparam
10
11 dsaparam data: openssl dsaparam -outform DER -out dsaparam.der 2048
12
13 @param dsaparam The DSA param DER encoded data
14 @param dsaparamlen The length of dhparam data
15 @param key [out] the destination for the imported key
16 @return CRYPT_OK if successful.
17 */
dsa_set_pqg_dsaparam(const unsigned char * dsaparam,unsigned long dsaparamlen,dsa_key * key)18 int dsa_set_pqg_dsaparam(const unsigned char *dsaparam, unsigned long dsaparamlen,
19 dsa_key *key)
20 {
21 int err, stat;
22
23 LTC_ARGCHK(dsaparam != NULL);
24 LTC_ARGCHK(key != NULL);
25 LTC_ARGCHK(ltc_mp.name != NULL);
26
27 /* init key */
28 err = mp_init_multi(&key->p, &key->g, &key->q, &key->x, &key->y, LTC_NULL);
29 if (err != CRYPT_OK) return err;
30
31 if ((err = der_decode_sequence_multi(dsaparam, dsaparamlen,
32 LTC_ASN1_INTEGER, 1UL, key->p,
33 LTC_ASN1_INTEGER, 1UL, key->q,
34 LTC_ASN1_INTEGER, 1UL, key->g,
35 LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
36 goto LBL_ERR;
37 }
38
39 key->qord = mp_unsigned_bin_size(key->q);
40
41 /* quick p, q, g validation, without primality testing */
42 if ((err = dsa_int_validate_pqg(key, &stat)) != CRYPT_OK) {
43 goto LBL_ERR;
44 }
45 if (stat == 0) {
46 err = CRYPT_INVALID_PACKET;
47 goto LBL_ERR;
48 }
49
50 return CRYPT_OK;
51
52 LBL_ERR:
53 dsa_free(key);
54 return err;
55 }
56
57 #endif
58