1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis */
2 /* SPDX-License-Identifier: Unlicense */
3 #include "tomcrypt_private.h"
4
5 /**
6 @file dsa_export.c
7 DSA implementation, export key, Tom St Denis
8 */
9
10 #ifdef LTC_MDSA
11
12 /**
13 Export a DSA key to a binary packet
14 @param out [out] Where to store the packet
15 @param outlen [in/out] The max size and resulting size of the packet
16 @param type The type of key to export (PK_PRIVATE or PK_PUBLIC)
17 @param key The key to export
18 @return CRYPT_OK if successful
19 */
dsa_export(unsigned char * out,unsigned long * outlen,int type,const dsa_key * key)20 int dsa_export(unsigned char *out, unsigned long *outlen, int type, const dsa_key *key)
21 {
22 unsigned long zero=0;
23 unsigned char flags[1];
24 int err, std;
25
26 LTC_ARGCHK(out != NULL);
27 LTC_ARGCHK(outlen != NULL);
28 LTC_ARGCHK(key != NULL);
29
30 std = type & PK_STD;
31 type &= ~PK_STD;
32
33 if (type == PK_PRIVATE && key->type != PK_PRIVATE) {
34 return CRYPT_PK_TYPE_MISMATCH;
35 }
36
37 if (type == PK_PRIVATE) {
38 if (std) {
39 return der_encode_sequence_multi(out, outlen,
40 LTC_ASN1_SHORT_INTEGER, 1UL, &zero,
41 LTC_ASN1_INTEGER, 1UL, key->p,
42 LTC_ASN1_INTEGER, 1UL, key->q,
43 LTC_ASN1_INTEGER, 1UL, key->g,
44 LTC_ASN1_INTEGER, 1UL, key->y,
45 LTC_ASN1_INTEGER, 1UL, key->x,
46 LTC_ASN1_EOL, 0UL, NULL);
47 }
48 flags[0] = 1;
49 return der_encode_sequence_multi(out, outlen,
50 LTC_ASN1_BIT_STRING, 1UL, flags,
51 LTC_ASN1_INTEGER, 1UL, key->g,
52 LTC_ASN1_INTEGER, 1UL, key->p,
53 LTC_ASN1_INTEGER, 1UL, key->q,
54 LTC_ASN1_INTEGER, 1UL, key->y,
55 LTC_ASN1_INTEGER, 1UL, key->x,
56 LTC_ASN1_EOL, 0UL, NULL);
57 }
58
59 if (type == PK_PUBLIC) {
60 if (std) {
61 unsigned long tmplen = (unsigned long)(mp_count_bits(key->y) / 8) + 8;
62 unsigned char* tmp = XMALLOC(tmplen);
63 ltc_asn1_list int_list[3];
64
65 if (tmp == NULL) {
66 return CRYPT_MEM;
67 }
68
69 err = der_encode_integer(key->y, tmp, &tmplen);
70 if (err != CRYPT_OK) {
71 goto error;
72 }
73
74 LTC_SET_ASN1(int_list, 0, LTC_ASN1_INTEGER, key->p, 1UL);
75 LTC_SET_ASN1(int_list, 1, LTC_ASN1_INTEGER, key->q, 1UL);
76 LTC_SET_ASN1(int_list, 2, LTC_ASN1_INTEGER, key->g, 1UL);
77
78 err = x509_encode_subject_public_key_info(out, outlen, LTC_OID_DSA, tmp,
79 tmplen, LTC_ASN1_SEQUENCE, int_list,
80 sizeof(int_list) / sizeof(int_list[0]));
81
82 error:
83 XFREE(tmp);
84 return err;
85 }
86 flags[0] = 0;
87 return der_encode_sequence_multi(out, outlen,
88 LTC_ASN1_BIT_STRING, 1UL, flags,
89 LTC_ASN1_INTEGER, 1UL, key->g,
90 LTC_ASN1_INTEGER, 1UL, key->p,
91 LTC_ASN1_INTEGER, 1UL, key->q,
92 LTC_ASN1_INTEGER, 1UL, key->y,
93 LTC_ASN1_EOL, 0UL, NULL);
94 }
95
96 return CRYPT_INVALID_ARG;
97 }
98
99 #endif
100
101