1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 *
9 * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com
10 */
11
12 /* Implements ECC over Z/pZ for curve y^2 = x^3 - 3x + b
13 *
14 * All curves taken from NIST recommendation paper of July 1999
15 * Available at http://csrc.nist.gov/cryptval/dss.htm
16 */
17 #include "tomcrypt.h"
18
19 /**
20 @file ecc_export.c
21 ECC Crypto, Tom St Denis
22 */
23
24 #ifdef MECC
25
26 /**
27 Export an ECC key as a binary packet
28 @param out [out] Destination for the key
29 @param outlen [in/out] Max size and resulting size of the exported key
30 @param type The type of key you want to export (PK_PRIVATE or PK_PUBLIC)
31 @param key The key to export
32 @return CRYPT_OK if successful
33 */
ecc_export(unsigned char * out,unsigned long * outlen,int type,ecc_key * key)34 int ecc_export(unsigned char *out, unsigned long *outlen, int type, ecc_key *key)
35 {
36 int err;
37 unsigned char flags[1];
38 unsigned long key_size;
39
40 LTC_ARGCHK(out != NULL);
41 LTC_ARGCHK(outlen != NULL);
42 LTC_ARGCHK(key != NULL);
43
44 /* type valid? */
45 if (key->type != PK_PRIVATE && type == PK_PRIVATE) {
46 return CRYPT_PK_TYPE_MISMATCH;
47 }
48
49 if (ltc_ecc_is_valid_idx(key->idx) == 0) {
50 return CRYPT_INVALID_ARG;
51 }
52
53 /* we store the NIST byte size */
54 key_size = key->dp->size;
55
56 if (type == PK_PRIVATE) {
57 flags[0] = 1;
58 err = der_encode_sequence_multi(out, outlen,
59 LTC_ASN1_BIT_STRING, 1UL, flags,
60 LTC_ASN1_SHORT_INTEGER, 1UL, &key_size,
61 LTC_ASN1_INTEGER, 1UL, key->pubkey.x,
62 LTC_ASN1_INTEGER, 1UL, key->pubkey.y,
63 LTC_ASN1_INTEGER, 1UL, key->k,
64 LTC_ASN1_EOL, 0UL, NULL);
65 } else {
66 flags[0] = 0;
67 err = der_encode_sequence_multi(out, outlen,
68 LTC_ASN1_BIT_STRING, 1UL, flags,
69 LTC_ASN1_SHORT_INTEGER, 1UL, &key_size,
70 LTC_ASN1_INTEGER, 1UL, key->pubkey.x,
71 LTC_ASN1_INTEGER, 1UL, key->pubkey.y,
72 LTC_ASN1_EOL, 0UL, NULL);
73 }
74
75 return err;
76 }
77
78 #endif
79 /* $Source: /cvs/libtom/libtomcrypt/src/pk/ecc/ecc_export.c,v $ */
80 /* $Revision: 1.4 $ */
81 /* $Date: 2006/11/21 00:10:18 $ */
82
83