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 /**
14 @file ecc_import.c
15 ECC Crypto, Tom St Denis
16 */
17
18 #ifdef LTC_MECC
19
20 /**
21 Import an ECC key from a binary packet
22 @param in The packet to import
23 @param inlen The length of the packet
24 @param key [out] The destination of the import
25 @return CRYPT_OK if successful, upon error all allocated memory will be freed
26 */
ecc_import(const unsigned char * in,unsigned long inlen,ecc_key * key)27 int ecc_import(const unsigned char *in, unsigned long inlen, ecc_key *key)
28 {
29 return ecc_import_ex(in, inlen, key, NULL);
30 }
31
32 /**
33 Import an ECC key from a binary packet, using user supplied domain params rather than one of the NIST ones
34 @param in The packet to import
35 @param inlen The length of the packet
36 @param key [out] The destination of the import
37 @param cu pointer to user supplied params; must be the same as the params used when exporting
38 @return CRYPT_OK if successful, upon error all allocated memory will be freed
39 */
ecc_import_ex(const unsigned char * in,unsigned long inlen,ecc_key * key,const ltc_ecc_curve * cu)40 int ecc_import_ex(const unsigned char *in, unsigned long inlen, ecc_key *key, const ltc_ecc_curve *cu)
41 {
42 unsigned long key_size;
43 unsigned char flags[1];
44 int err;
45
46 LTC_ARGCHK(in != NULL);
47 LTC_ARGCHK(key != NULL);
48 LTC_ARGCHK(ltc_mp.name != NULL);
49
50 /* find out what type of key it is */
51 err = der_decode_sequence_multi(in, inlen, LTC_ASN1_BIT_STRING, 1UL, flags,
52 LTC_ASN1_SHORT_INTEGER, 1UL, &key_size,
53 LTC_ASN1_EOL, 0UL, NULL);
54 if (err != CRYPT_OK && err != CRYPT_INPUT_TOO_LONG) {
55 return err;
56 }
57
58 /* allocate & initialize the key */
59 if (cu == NULL) {
60 if ((err = ecc_set_curve_by_size(key_size, key)) != CRYPT_OK) { goto done; }
61 } else {
62 if ((err = ecc_set_curve(cu, key)) != CRYPT_OK) { goto done; }
63 }
64
65 if (flags[0] == 1) {
66 /* private key */
67 key->type = PK_PRIVATE;
68 if ((err = der_decode_sequence_multi(in, inlen,
69 LTC_ASN1_BIT_STRING, 1UL, flags,
70 LTC_ASN1_SHORT_INTEGER, 1UL, &key_size,
71 LTC_ASN1_INTEGER, 1UL, key->pubkey.x,
72 LTC_ASN1_INTEGER, 1UL, key->pubkey.y,
73 LTC_ASN1_INTEGER, 1UL, key->k,
74 LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
75 goto done;
76 }
77 } else if (flags[0] == 0) {
78 /* public key */
79 key->type = PK_PUBLIC;
80 if ((err = der_decode_sequence_multi(in, inlen,
81 LTC_ASN1_BIT_STRING, 1UL, flags,
82 LTC_ASN1_SHORT_INTEGER, 1UL, &key_size,
83 LTC_ASN1_INTEGER, 1UL, key->pubkey.x,
84 LTC_ASN1_INTEGER, 1UL, key->pubkey.y,
85 LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
86 goto done;
87 }
88 }
89 else {
90 err = CRYPT_INVALID_PACKET;
91 goto done;
92 }
93
94 /* set z */
95 if ((err = mp_set(key->pubkey.z, 1)) != CRYPT_OK) { goto done; }
96
97 /* point on the curve + other checks */
98 if ((err = ltc_ecc_verify_key(key)) != CRYPT_OK) { goto done; }
99
100 /* we're good */
101 return CRYPT_OK;
102
103 done:
104 ecc_free(key);
105 return err;
106 }
107 #endif
108 /* ref: $Format:%D$ */
109 /* git commit: $Format:%H$ */
110 /* commit time: $Format:%ai$ */
111
112