tomcrypt/dsa_export.c
2010-06-16 12:38:11 +02:00

63 lines
1.4 KiB
C

/* 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@iahu.ca, http://libtomcrypt.org
*/
#include "mycrypt.h"
#ifdef MDSA
int dsa_export(unsigned char *out, unsigned long *outlen, int type, dsa_key *key)
{
unsigned long y, z;
int err;
_ARGCHK(out != NULL);
_ARGCHK(outlen != NULL);
_ARGCHK(key != NULL);
/* can we store the static header? */
if (*outlen < (PACKET_SIZE + 1 + 2)) {
return CRYPT_BUFFER_OVERFLOW;
}
if (type == PK_PRIVATE && key->type != PK_PRIVATE) {
return CRYPT_PK_TYPE_MISMATCH;
}
if (type != PK_PUBLIC && type != PK_PRIVATE) {
return CRYPT_INVALID_ARG;
}
/* store header */
packet_store_header(out, PACKET_SECT_DSA, PACKET_SUB_KEY);
y = PACKET_SIZE;
/* store g, p, q, qord */
out[y++] = type;
out[y++] = (key->qord>>8)&255;
out[y++] = key->qord & 255;
OUTPUT_BIGNUM(&key->g,out,y,z);
OUTPUT_BIGNUM(&key->p,out,y,z);
OUTPUT_BIGNUM(&key->q,out,y,z);
/* public exponent */
OUTPUT_BIGNUM(&key->y,out,y,z);
if (type == PK_PRIVATE) {
OUTPUT_BIGNUM(&key->x,out,y,z);
}
*outlen = y;
return CRYPT_OK;
}
#endif