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/* LibTomCrypt, modular cryptographic library -- Tom St Denis
*
* LibTomCrypt is a library that provides various cryptographic
* algorithms in a highly modular and flexible manner.
*
* The library is free for all purposes without any express
* guarantee it works.
*
* Tom St Denis, tomstdenis@gmail.com, http://libtom.org
*/
/* Implements ECC over Z/pZ for curve y^2 = x^3 - 3x + b
*
* All curves taken from NIST recommendation paper of July 1999
* Available at http://csrc.nist.gov/cryptval/dss.htm
*/
#include "tomcrypt.h"
/**
@file ecc_ansi_x963_export.c
ECC Crypto, Tom St Denis
*/
#ifdef LTC_MECC
/** ECC X9.63 (Sec. 4.3.6) uncompressed export
@param key Key to export
@param out [out] destination of export
@param outlen [in/out] Length of destination and final output size
Return CRYPT_OK on success
*/
int ecc_ansi_x963_export(ecc_key *key, unsigned char *out, unsigned long *outlen)
{
unsigned char buf[ECC_BUF_SIZE];
unsigned long numlen;
LTC_ARGCHK(key != NULL);
LTC_ARGCHK(out != NULL);
LTC_ARGCHK(outlen != NULL);
if (ltc_ecc_is_valid_idx(key->idx) == 0) {
return CRYPT_INVALID_ARG;
}
numlen = key->dp->size;
if (*outlen < (1 + 2*numlen)) {
*outlen = 1 + 2*numlen;
return CRYPT_BUFFER_OVERFLOW;
}
/* store byte 0x04 */
out[0] = 0x04;
/* pad and store x */
zeromem(buf, sizeof(buf));
mp_to_unsigned_bin(key->pubkey.x, buf + (numlen - mp_unsigned_bin_size(key->pubkey.x)));
XMEMCPY(out+1, buf, numlen);
/* pad and store y */
zeromem(buf, sizeof(buf));
mp_to_unsigned_bin(key->pubkey.y, buf + (numlen - mp_unsigned_bin_size(key->pubkey.y)));
XMEMCPY(out+1+numlen, buf, numlen);
*outlen = 1 + 2*numlen;
return CRYPT_OK;
}
#endif
/* $Source$ */
/* $Revision$ */
/* $Date$ */
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