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comparison libtomcrypt/src/pk/ecc/ecc_ansi_x963_export.c @ 435:337c45621e81

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merge of 'a9b0496634cdd25647b65e585cc3240f3fa699ee' and 'c22be8b8f570b48e9662dac32c7b3e7148a42206'
author Matt Johnston <matt@ucc.asn.au>
date Thu, 22 Feb 2007 14:53:49 +0000
parents 0cbe8f6dbf9e
children f849a5ca2efc
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434:0aaaf68e97dc 435:337c45621e81
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, [email protected], 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_ansi_x963_export.c
21 ECC Crypto, Tom St Denis
22 */
23
24 #ifdef MECC
25
26 /** ECC X9.63 (Sec. 4.3.6) uncompressed export
27 @param key Key to export
28 @param out [out] destination of export
29 @param outlen [in/out] Length of destination and final output size
30 Return CRYPT_OK on success
31 */
32 int ecc_ansi_x963_export(ecc_key *key, unsigned char *out, unsigned long *outlen)
33 {
34 unsigned char buf[ECC_BUF_SIZE];
35 unsigned long numlen;
36
37 LTC_ARGCHK(key != NULL);
38 LTC_ARGCHK(out != NULL);
39 LTC_ARGCHK(outlen != NULL);
40
41 if (ltc_ecc_is_valid_idx(key->idx) == 0) {
42 return CRYPT_INVALID_ARG;
43 }
44 numlen = key->dp->size;
45
46 if (*outlen < (1 + 2*numlen)) {
47 *outlen = 1 + 2*numlen;
48 return CRYPT_BUFFER_OVERFLOW;
49 }
50
51 /* store byte 0x04 */
52 out[0] = 0x04;
53
54 /* pad and store x */
55 zeromem(buf, sizeof(buf));
56 mp_to_unsigned_bin(key->pubkey.x, buf + (numlen - mp_unsigned_bin_size(key->pubkey.x)));
57 XMEMCPY(out+1, buf, numlen);
58
59 /* pad and store y */
60 zeromem(buf, sizeof(buf));
61 mp_to_unsigned_bin(key->pubkey.y, buf + (numlen - mp_unsigned_bin_size(key->pubkey.y)));
62 XMEMCPY(out+1+numlen, buf, numlen);
63
64 *outlen = 1 + 2*numlen;
65 return CRYPT_OK;
66 }
67
68 #endif
69
70 /* $Source: /cvs/libtom/libtomcrypt/src/pk/ecc/ecc_ansi_x963_export.c,v $ */
71 /* $Revision: 1.4 $ */
72 /* $Date: 2006/12/04 02:50:11 $ */