1 // SPDX-License-Identifier: BSD-2-Clause
2 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
3 *
4 * LibTomCrypt is a library that provides various cryptographic
5 * algorithms in a highly modular and flexible manner.
6 *
7 * The library is free for all purposes without any express
8 * guarantee it works.
9 */
10
11 #include "tomcrypt_private.h"
12
13 #ifdef LTC_MDH
14
15 /**
16 Import DH key parts p and g from raw numbers
17
18 @param p DH's p (prime)
19 @param plen DH's p's length
20 @param g DH's g (group)
21 @param glen DH's g's length
22 @param key [out] the destination for the imported key
23 @return CRYPT_OK if successful
24 */
dh_set_pg(const unsigned char * p,unsigned long plen,const unsigned char * g,unsigned long glen,dh_key * key)25 int dh_set_pg(const unsigned char *p, unsigned long plen,
26 const unsigned char *g, unsigned long glen,
27 dh_key *key)
28 {
29 int err;
30
31 LTC_ARGCHK(key != NULL);
32 LTC_ARGCHK(p != NULL);
33 LTC_ARGCHK(g != NULL);
34 LTC_ARGCHK(ltc_mp.name != NULL);
35
36 if ((err = mp_init_multi(&key->x, &key->y, &key->base, &key->prime, NULL)) != CRYPT_OK) {
37 return err;
38 }
39
40 if ((err = mp_read_unsigned_bin(key->base, (unsigned char*)g, glen)) != CRYPT_OK) { goto LBL_ERR; }
41 if ((err = mp_read_unsigned_bin(key->prime, (unsigned char*)p, plen)) != CRYPT_OK) { goto LBL_ERR; }
42
43 return CRYPT_OK;
44
45 LBL_ERR:
46 dh_free(key);
47 return err;
48 }
49
50 /**
51 Import DH key parts p and g from built-in DH groups
52
53 @param groupsize The size of the DH group to use
54 @param key [out] Where the newly created DH key will be stored
55 @return CRYPT_OK if successful, note: on error all allocated memory will be freed automatically.
56 */
dh_set_pg_groupsize(int groupsize,dh_key * key)57 int dh_set_pg_groupsize(int groupsize, dh_key *key)
58 {
59 int err, i;
60
61 LTC_ARGCHK(key != NULL);
62 LTC_ARGCHK(ltc_mp.name != NULL);
63 LTC_ARGCHK(groupsize > 0);
64
65 for (i = 0; (groupsize > ltc_dh_sets[i].size) && (ltc_dh_sets[i].size != 0); i++);
66 if (ltc_dh_sets[i].size == 0) return CRYPT_INVALID_KEYSIZE;
67
68 if ((err = mp_init_multi(&key->x, &key->y, &key->base, &key->prime, NULL)) != CRYPT_OK) {
69 return err;
70 }
71 if ((err = mp_read_radix(key->base, ltc_dh_sets[i].base, 16)) != CRYPT_OK) { goto LBL_ERR; }
72 if ((err = mp_read_radix(key->prime, ltc_dh_sets[i].prime, 16)) != CRYPT_OK) { goto LBL_ERR; }
73
74 return CRYPT_OK;
75
76 LBL_ERR:
77 dh_free(key);
78 return err;
79 }
80
81 /**
82 Import DH public or private key part from raw numbers
83
84 NB: The p & g parts must be set beforehand
85
86 @param in The key-part to import, either public or private.
87 @param inlen The key-part's length
88 @param type Which type of key (PK_PRIVATE or PK_PUBLIC)
89 @param key [out] the destination for the imported key
90 @return CRYPT_OK if successful
91 */
dh_set_key(const unsigned char * in,unsigned long inlen,int type,dh_key * key)92 int dh_set_key(const unsigned char *in, unsigned long inlen, int type, dh_key *key)
93 {
94 int err;
95
96 LTC_ARGCHK(key != NULL);
97 LTC_ARGCHK(ltc_mp.name != NULL);
98
99 if (type == PK_PRIVATE) {
100 key->type = PK_PRIVATE;
101 if ((err = mp_read_unsigned_bin(key->x, (unsigned char*)in, inlen)) != CRYPT_OK) { goto LBL_ERR; }
102 if ((err = mp_exptmod(key->base, key->x, key->prime, key->y)) != CRYPT_OK) { goto LBL_ERR; }
103 }
104 else {
105 key->type = PK_PUBLIC;
106 if ((err = mp_read_unsigned_bin(key->y, (unsigned char*)in, inlen)) != CRYPT_OK) { goto LBL_ERR; }
107 }
108
109 /* check public key */
110 if ((err = dh_check_pubkey(key)) != CRYPT_OK) {
111 goto LBL_ERR;
112 }
113
114 return CRYPT_OK;
115
116 LBL_ERR:
117 dh_free(key);
118 return err;
119 }
120
121 #endif /* LTC_MDH */
122
123 /* ref: $Format:%D$ */
124 /* git commit: $Format:%H$ */
125 /* commit time: $Format:%ai$ */
126