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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
*/
#include "tomcrypt.h"
/**
@file dsa_export.c
DSA implementation, export key, Tom St Denis
*/
#ifdef LTC_MDSA
/**
Export a DSA key to a binary packet
@param out [out] Where to store the packet
@param outlen [in/out] The max size and resulting size of the packet
@param type The type of key to export (PK_PRIVATE or PK_PUBLIC)
@param key The key to export
@return CRYPT_OK if successful
*/
int dsa_export(unsigned char *out, unsigned long *outlen, int type,
dsa_key * key)
{
unsigned long zero = 0;
int err;
LTC_ARGCHK(out != NULL);
LTC_ARGCHK(outlen != NULL);
LTC_ARGCHK(key != NULL);
/* can we store the static header? */
if (type == PK_PRIVATE && key->type != PK_PRIVATE) {
return CRYPT_PK_TYPE_MISMATCH;
}
if (type != PK_PUBLIC && type != PK_PRIVATE) {
return CRYPT_INVALID_ARG;
}
/* This encoding is different from the one in original
* libtomcrypt. It uses a compatible encoding with gnutls
* and openssl
*/
if (type == PK_PRIVATE) {
return der_encode_sequence_multi(out, outlen,
LTC_ASN1_SHORT_INTEGER, 1UL,
&zero, LTC_ASN1_INTEGER, 1UL,
&key->p, LTC_ASN1_INTEGER, 1UL,
&key->q, LTC_ASN1_INTEGER, 1UL,
&key->g, LTC_ASN1_INTEGER, 1UL,
&key->y, LTC_ASN1_INTEGER, 1UL,
&key->x, LTC_ASN1_EOL, 0UL,
NULL);
} else {
unsigned long tmplen = (mp_count_bits(&key->y) / 8) + 8;
unsigned char *tmp = XMALLOC(tmplen);
ltc_asn1_list int_list[3];
if (tmp == NULL) {
return CRYPT_MEM;
}
err = der_encode_integer(&key->y, tmp, &tmplen);
if (err != CRYPT_OK) {
goto error;
}
int_list[0].data = &key->p;
int_list[0].size = 1UL;
int_list[0].type = LTC_ASN1_INTEGER;
int_list[1].data = &key->q;
int_list[1].size = 1UL;
int_list[1].type = LTC_ASN1_INTEGER;
int_list[2].data = &key->g;
int_list[2].size = 1UL;
int_list[2].type = LTC_ASN1_INTEGER;
err = der_encode_subject_public_key_info(out, outlen,
PKA_DSA, tmp, tmplen,
LTC_ASN1_SEQUENCE,
int_list,
sizeof(int_list) /
sizeof(int_list[0]));
error:
XFREE(tmp);
return err;
}
}
#endif
/* $Source: /cvs/libtom/libtomcrypt/src/pk/dsa/dsa_export.c,v $ */
/* $Revision: 1.10 $ */
/* $Date: 2007/05/12 14:32:35 $ */
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