mirror of
https://github.com/Laupetin/OpenAssetTools.git
synced 2025-04-21 16:45:44 +00:00
129 lines
3.7 KiB
C
129 lines
3.7 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.
|
|
*/
|
|
#include "tomcrypt.h"
|
|
|
|
/**
|
|
@file dsa_encrypt_key.c
|
|
DSA Crypto, Tom St Denis
|
|
*/
|
|
|
|
#ifdef LTC_MDSA
|
|
|
|
/**
|
|
Encrypt a symmetric key with DSA
|
|
@param in The symmetric key you want to encrypt
|
|
@param inlen The length of the key to encrypt (octets)
|
|
@param out [out] The destination for the ciphertext
|
|
@param outlen [in/out] The max size and resulting size of the ciphertext
|
|
@param prng An active PRNG state
|
|
@param wprng The index of the PRNG you wish to use
|
|
@param hash The index of the hash you want to use
|
|
@param key The DSA key you want to encrypt to
|
|
@return CRYPT_OK if successful
|
|
*/
|
|
int dsa_encrypt_key(const unsigned char *in, unsigned long inlen,
|
|
unsigned char *out, unsigned long *outlen,
|
|
prng_state *prng, int wprng, int hash,
|
|
dsa_key *key)
|
|
{
|
|
unsigned char *expt, *skey;
|
|
void *g_pub, *g_priv;
|
|
unsigned long x, y;
|
|
int err;
|
|
|
|
LTC_ARGCHK(in != NULL);
|
|
LTC_ARGCHK(out != NULL);
|
|
LTC_ARGCHK(outlen != NULL);
|
|
LTC_ARGCHK(key != NULL);
|
|
|
|
/* check that wprng/cipher/hash are not invalid */
|
|
if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
|
|
return err;
|
|
}
|
|
|
|
if ((err = hash_is_valid(hash)) != CRYPT_OK) {
|
|
return err;
|
|
}
|
|
|
|
if (inlen > hash_descriptor[hash].hashsize) {
|
|
return CRYPT_INVALID_HASH;
|
|
}
|
|
|
|
/* make a random key and export the public copy */
|
|
if ((err = mp_init_multi(&g_pub, &g_priv, NULL)) != CRYPT_OK) {
|
|
return err;
|
|
}
|
|
|
|
expt = XMALLOC(mp_unsigned_bin_size(key->p) + 1);
|
|
skey = XMALLOC(MAXBLOCKSIZE);
|
|
if (expt == NULL || skey == NULL) {
|
|
if (expt != NULL) {
|
|
XFREE(expt);
|
|
}
|
|
if (skey != NULL) {
|
|
XFREE(skey);
|
|
}
|
|
mp_clear_multi(g_pub, g_priv, NULL);
|
|
return CRYPT_MEM;
|
|
}
|
|
|
|
/* make a random g_priv, g_pub = g^x pair
|
|
private key x should be in range: 1 <= x <= q-1 (see FIPS 186-4 B.1.2)
|
|
*/
|
|
if ((err = rand_bn_upto(g_priv, key->q, prng, wprng)) != CRYPT_OK) {
|
|
goto LBL_ERR;
|
|
}
|
|
|
|
/* compute y */
|
|
if ((err = mp_exptmod(key->g, g_priv, key->p, g_pub)) != CRYPT_OK) {
|
|
goto LBL_ERR;
|
|
}
|
|
|
|
/* make random key */
|
|
x = mp_unsigned_bin_size(key->p) + 1;
|
|
if ((err = dsa_shared_secret(g_priv, key->y, key, expt, &x)) != CRYPT_OK) {
|
|
goto LBL_ERR;
|
|
}
|
|
|
|
y = MAXBLOCKSIZE;
|
|
if ((err = hash_memory(hash, expt, x, skey, &y)) != CRYPT_OK) {
|
|
goto LBL_ERR;
|
|
}
|
|
|
|
/* Encrypt key */
|
|
for (x = 0; x < inlen; x++) {
|
|
skey[x] ^= in[x];
|
|
}
|
|
|
|
err = der_encode_sequence_multi(out, outlen,
|
|
LTC_ASN1_OBJECT_IDENTIFIER, hash_descriptor[hash].OIDlen, hash_descriptor[hash].OID,
|
|
LTC_ASN1_INTEGER, 1UL, g_pub,
|
|
LTC_ASN1_OCTET_STRING, inlen, skey,
|
|
LTC_ASN1_EOL, 0UL, NULL);
|
|
|
|
LBL_ERR:
|
|
#ifdef LTC_CLEAN_STACK
|
|
/* clean up */
|
|
zeromem(expt, mp_unsigned_bin_size(key->p) + 1);
|
|
zeromem(skey, MAXBLOCKSIZE);
|
|
#endif
|
|
|
|
XFREE(skey);
|
|
XFREE(expt);
|
|
|
|
mp_clear_multi(g_pub, g_priv, NULL);
|
|
return err;
|
|
}
|
|
|
|
#endif
|
|
/* ref: HEAD -> master, tag: v1.18.2 */
|
|
/* git commit: 7e7eb695d581782f04b24dc444cbfde86af59853 */
|
|
/* commit time: 2018-07-01 22:49:01 +0200 */
|
|
|