2 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
12 #include "internal/cryptlib.h"
13 #include <openssl/bn.h>
15 #include <openssl/rand.h>
17 static int dsa_builtin_keygen(DSA *dsa);
19 int DSA_generate_key(DSA *dsa)
21 if (dsa->meth->dsa_keygen)
22 return dsa->meth->dsa_keygen(dsa);
23 return dsa_builtin_keygen(dsa);
26 static int dsa_builtin_keygen(DSA *dsa)
30 BIGNUM *pub_key = NULL, *priv_key = NULL;
32 if ((ctx = BN_CTX_new()) == NULL)
35 if (dsa->priv_key == NULL) {
36 if ((priv_key = BN_secure_new()) == NULL)
39 priv_key = dsa->priv_key;
42 if (!BN_rand_range(priv_key, dsa->q))
44 while (BN_is_zero(priv_key)) ;
46 if (dsa->pub_key == NULL) {
47 if ((pub_key = BN_new()) == NULL)
50 pub_key = dsa->pub_key;
53 BIGNUM *local_prk = NULL;
56 if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) {
57 local_prk = prk = BN_new();
58 if (local_prk == NULL)
60 BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
65 if (!BN_mod_exp(pub_key, dsa->g, prk, dsa->p, ctx)) {
69 /* We MUST free local_prk before any further use of priv_key */
73 dsa->priv_key = priv_key;
74 dsa->pub_key = pub_key;
78 if (pub_key != dsa->pub_key)
80 if (priv_key != dsa->priv_key)