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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://libtomcrypt.org
*/
#include "tomcrypt.h"
/**
@file dsa_import.c
DSA implementation, import a DSA key, Tom St Denis
*/
#ifdef MDSA
/**
Import a DSA key
@param in The binary packet to import from
@param inlen The length of the binary packet
@param key [out] Where to store the imported key
@return CRYPT_OK if successful, upon error this function will free all allocated memory
*/
int dsa_import(const unsigned char *in, unsigned long inlen, dsa_key *key)
{
unsigned char flags[1];
int err;
LTC_ARGCHK(in != NULL);
LTC_ARGCHK(key != NULL);
/* init key */
if (mp_init_multi(&key->p, &key->g, &key->q, &key->x, &key->y, NULL) != MP_OKAY) {
return CRYPT_MEM;
}
/* get key type */
if ((err = der_decode_sequence_multi(in, inlen,
LTC_ASN1_BIT_STRING, 1UL, flags,
LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
goto error;
}
if (flags[0] == 1) {
if ((err = der_decode_sequence_multi(in, inlen,
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)) != CRYPT_OK) {
goto error;
}
key->type = PK_PRIVATE;
} else {
if ((err = der_decode_sequence_multi(in, inlen,
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)) != CRYPT_OK) {
goto error;
}
key->type = PK_PUBLIC;
}
key->qord = mp_unsigned_bin_size(&key->q);
if (key->qord >= MDSA_MAX_GROUP || key->qord <= 15 ||
key->qord >= mp_unsigned_bin_size(&key->p) || (mp_unsigned_bin_size(&key->p) - key->qord) >= MDSA_DELTA) {
err = CRYPT_INVALID_PACKET;
goto error;
}
return CRYPT_OK;
error:
mp_clear_multi(&key->p, &key->g, &key->q, &key->x, &key->y, NULL);
return err;
}
#endif
/* $Source: /cvs/libtom/libtomcrypt/src/pk/dsa/dsa_import.c,v $ */
/* $Revision: 1.7 $ */
/* $Date: 2005/06/08 23:31:17 $ */
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