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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.
*/
#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, std;
LTC_ARGCHK(out != NULL);
LTC_ARGCHK(outlen != NULL);
LTC_ARGCHK(key != NULL);
std = type & PK_STD;
type &= ~PK_STD;
/* 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;
}
if (type == PK_PRIVATE) {
if (std) {
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 char flags[1];
flags[0] = 1;
return der_encode_sequence_multi(out, outlen,
LTC_ASN1_BIT_STRING, 1UL, flags,
LTC_ASN1_INTEGER, 1UL, key->g,
LTC_ASN1_INTEGER, 1UL, key->p,
LTC_ASN1_INTEGER, 1UL, key->q,
LTC_ASN1_INTEGER, 1UL, key->y,
LTC_ASN1_INTEGER, 1UL, key->x,
LTC_ASN1_EOL, 0UL, NULL);
}
} else {
if (std) {
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;
}
LTC_SET_ASN1(int_list, 0, LTC_ASN1_INTEGER, key->p, 1UL);
LTC_SET_ASN1(int_list, 1, LTC_ASN1_INTEGER, key->q, 1UL);
LTC_SET_ASN1(int_list, 2, LTC_ASN1_INTEGER, key->g, 1UL);
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;
}
else {
unsigned char flags[1];
flags[0] = 0;
return der_encode_sequence_multi(out, outlen,
LTC_ASN1_BIT_STRING, 1UL, flags,
LTC_ASN1_INTEGER, 1UL, key->g,
LTC_ASN1_INTEGER, 1UL, key->p,
LTC_ASN1_INTEGER, 1UL, key->q,
LTC_ASN1_INTEGER, 1UL, key->y,
LTC_ASN1_EOL, 0UL, NULL);
}
}
}
#endif
/* ref: $Format:%D$ */
/* git commit: $Format:%H$ */
/* commit time: $Format:%ai$ */
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