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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_export.c
ECC Crypto, Tom St Denis
*/
#if defined(LTC_MECC) && defined(LTC_DER)
/**
Export an ECC key as a binary packet
@param out [out] Destination for the key
@param outlen [in/out] Max size and resulting size of the exported key
@param type The type of key you want to export (PK_PRIVATE or PK_PUBLIC)
@param key The key to export
@return CRYPT_OK if successful
*/
int ecc_export(unsigned char *out, unsigned long *outlen, int type, ecc_key *key)
{
int err;
unsigned char flags[1];
unsigned long key_size;
LTC_ARGCHK(out != NULL);
LTC_ARGCHK(outlen != NULL);
LTC_ARGCHK(key != NULL);
/* type valid? */
if (key->type != PK_PRIVATE && type == PK_PRIVATE) {
return CRYPT_PK_TYPE_MISMATCH;
}
if (ltc_ecc_is_valid_idx(key->idx) == 0) {
return CRYPT_INVALID_ARG;
}
/* we store the NIST byte size */
key_size = key->dp->size;
if (type == PK_PRIVATE) {
flags[0] = 1;
err = der_encode_sequence_multi(out, outlen,
LTC_ASN1_BIT_STRING, 1UL, flags,
LTC_ASN1_SHORT_INTEGER, 1UL, &key_size,
LTC_ASN1_INTEGER, 1UL, key->pubkey.x,
LTC_ASN1_INTEGER, 1UL, key->pubkey.y,
LTC_ASN1_INTEGER, 1UL, key->k,
LTC_ASN1_EOL, 0UL, NULL);
} else {
flags[0] = 0;
err = der_encode_sequence_multi(out, outlen,
LTC_ASN1_BIT_STRING, 1UL, flags,
LTC_ASN1_SHORT_INTEGER, 1UL, &key_size,
LTC_ASN1_INTEGER, 1UL, key->pubkey.x,
LTC_ASN1_INTEGER, 1UL, key->pubkey.y,
LTC_ASN1_EOL, 0UL, NULL);
}
return err;
}
#endif
/* $Source$ */
/* $Revision$ */
/* $Date$ */
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