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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_import.c
ECC Crypto, Tom St Denis
*/
#ifdef LTC_MECC
/** Import an ANSI X9.63 format public key
@param in The input data to read
@param inlen The length of the input data
@param key [out] destination to store imported key \
*/
int ecc_ansi_x963_import(const unsigned char *in, unsigned long inlen, ecc_key *key)
{
return ecc_ansi_x963_import_ex(in, inlen, key, NULL);
}
int ecc_ansi_x963_import_ex(const unsigned char *in, unsigned long inlen, ecc_key *key, ltc_ecc_set_type *dp)
{
int x, err;
LTC_ARGCHK(in != NULL);
LTC_ARGCHK(key != NULL);
/* must be odd */
if ((inlen & 1) == 0) {
return CRYPT_INVALID_ARG;
}
/* init key */
if (mp_init_multi(&key->pubkey.x, &key->pubkey.y, &key->pubkey.z, &key->k, NULL) != CRYPT_OK) {
return CRYPT_MEM;
}
/* check for 4, 6 or 7 */
if (in[0] != 4 && in[0] != 6 && in[0] != 7) {
err = CRYPT_INVALID_PACKET;
goto error;
}
/* read data */
if ((err = mp_read_unsigned_bin(key->pubkey.x, (unsigned char *)in+1, (inlen-1)>>1)) != CRYPT_OK) {
goto error;
}
if ((err = mp_read_unsigned_bin(key->pubkey.y, (unsigned char *)in+1+((inlen-1)>>1), (inlen-1)>>1)) != CRYPT_OK) {
goto error;
}
if ((err = mp_set(key->pubkey.z, 1)) != CRYPT_OK) { goto error; }
if (dp == NULL) {
/* determine the idx */
for (x = 0; ltc_ecc_sets[x].size != 0; x++) {
if ((unsigned)ltc_ecc_sets[x].size >= ((inlen-1)>>1)) {
break;
}
}
if (ltc_ecc_sets[x].size == 0) {
err = CRYPT_INVALID_PACKET;
goto error;
}
/* set the idx */
key->idx = x;
key->dp = <c_ecc_sets[x];
} else {
if (((inlen-1)>>1) != (unsigned long) dp->size) {
err = CRYPT_INVALID_PACKET;
goto error;
}
key->idx = -1;
key->dp = dp;
}
key->type = PK_PUBLIC;
/* we're done */
return CRYPT_OK;
error:
mp_clear_multi(key->pubkey.x, key->pubkey.y, key->pubkey.z, key->k, NULL);
return err;
}
#endif
/* $Source$ */
/* $Revision$ */
/* $Date$ */
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