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 Export a DH key to a binary packet
17 @param out [out] The destination for the key
18 @param outlen [in/out] The max size and resulting size of the DH key
19 @param type Which type of key (PK_PRIVATE or PK_PUBLIC)
20 @param key The key you wish to export
21 @return CRYPT_OK if successful
22 */
dh_export(unsigned char * out,unsigned long * outlen,int type,const dh_key * key)23 int dh_export(unsigned char *out, unsigned long *outlen, int type, const dh_key *key)
24 {
25 unsigned char flags[1];
26 int err;
27 unsigned long version = 0;
28
29 LTC_ARGCHK(out != NULL);
30 LTC_ARGCHK(outlen != NULL);
31 LTC_ARGCHK(key != NULL);
32
33 if (type == PK_PRIVATE) {
34 /* export x - private key */
35 flags[0] = 1;
36 err = der_encode_sequence_multi(out, outlen,
37 LTC_ASN1_SHORT_INTEGER, 1UL, &version,
38 LTC_ASN1_BIT_STRING, 1UL, flags,
39 LTC_ASN1_INTEGER, 1UL, key->prime,
40 LTC_ASN1_INTEGER, 1UL, key->base,
41 LTC_ASN1_INTEGER, 1UL, key->x,
42 LTC_ASN1_EOL, 0UL, NULL);
43 }
44 else {
45 /* export y - public key */
46 flags[0] = 0;
47 err = der_encode_sequence_multi(out, outlen,
48 LTC_ASN1_SHORT_INTEGER, 1UL, &version,
49 LTC_ASN1_BIT_STRING, 1UL, flags,
50 LTC_ASN1_INTEGER, 1UL, key->prime,
51 LTC_ASN1_INTEGER, 1UL, key->base,
52 LTC_ASN1_INTEGER, 1UL, key->y,
53 LTC_ASN1_EOL, 0UL, NULL);
54 }
55
56 return err;
57 }
58
59 #endif /* LTC_MDH */
60
61 /* ref: $Format:%D$ */
62 /* git commit: $Format:%H$ */
63 /* commit time: $Format:%ai$ */
64