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*/
34int 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