1
/* crypto/dh/dh_key.c */
2
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
5
* This package is an SSL implementation written
6
* by Eric Young (eay@cryptsoft.com).
7
* The implementation was written so as to conform with Netscapes SSL.
9
* This library is free for commercial and non-commercial use as long as
10
* the following conditions are aheared to. The following conditions
11
* apply to all code found in this distribution, be it the RC4, RSA,
12
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
13
* included with this distribution is covered by the same copyright terms
14
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
16
* Copyright remains Eric Young's, and as such any Copyright notices in
17
* the code are not to be removed.
18
* If this package is used in a product, Eric Young should be given attribution
19
* as the author of the parts of the library used.
20
* This can be in the form of a textual message at program startup or
21
* in documentation (online or textual) provided with the package.
23
* Redistribution and use in source and binary forms, with or without
24
* modification, are permitted provided that the following conditions
26
* 1. Redistributions of source code must retain the copyright
27
* notice, this list of conditions and the following disclaimer.
28
* 2. Redistributions in binary form must reproduce the above copyright
29
* notice, this list of conditions and the following disclaimer in the
30
* documentation and/or other materials provided with the distribution.
31
* 3. All advertising materials mentioning features or use of this software
32
* must display the following acknowledgement:
33
* "This product includes cryptographic software written by
34
* Eric Young (eay@cryptsoft.com)"
35
* The word 'cryptographic' can be left out if the rouines from the library
36
* being used are not cryptographic related :-).
37
* 4. If you include any Windows specific code (or a derivative thereof) from
38
* the apps directory (application code) you must include an acknowledgement:
39
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
41
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
53
* The licence and distribution terms for any publically available version or
54
* derivative of this code cannot be changed. i.e. this code cannot simply be
55
* copied and put under another distribution licence
56
* [including the GNU Public Licence.]
60
#include <openssl/err.h>
61
#include <openssl/bn.h>
62
#ifndef OPENSSL_NO_RAND
63
#include <openssl/rand.h>
66
#include <openssl/dh.h>
70
static int generate_key(DH *dh);
71
static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh);
72
static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
73
const BIGNUM *a, const BIGNUM *p,
74
const BIGNUM *m, BN_CTX *ctx,
76
static int dh_init(DH *dh);
77
static int dh_finish(DH *dh);
79
int DH_generate_key(DH *dh)
81
return dh->meth->generate_key(dh);
84
int DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
86
return dh->meth->compute_key(key, pub_key, dh);
89
static DH_METHOD dh_ossl = {
100
const DH_METHOD *DH_OpenSSL(void)
105
static int generate_key(DH *dh)
108
int generate_new_key=0;
112
BIGNUM *pub_key=NULL,*priv_key=NULL;
115
if (ctx == NULL) goto err;
117
if (dh->priv_key == NULL)
120
if (priv_key == NULL) goto err;
124
priv_key=dh->priv_key;
126
if (dh->pub_key == NULL)
129
if (pub_key == NULL) goto err;
134
if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P))
136
if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
137
if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p,
138
dh->p,ctx)) goto err;
140
mont=(BN_MONT_CTX *)dh->method_mont_p;
142
if (generate_new_key)
144
l = dh->length ? dh->length : BN_num_bits(dh->p)-1; /* secret exponent length */
145
if (!BN_rand(priv_key, l, 0, 0)) goto err;
147
if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, priv_key,dh->p,ctx,mont))
151
dh->priv_key=priv_key;
155
DHerr(DH_F_DH_GENERATE_KEY,ERR_R_BN_LIB);
157
if ((pub_key != NULL) && (dh->pub_key == NULL)) BN_free(pub_key);
158
if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key);
163
static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
171
if (ctx == NULL) goto err;
173
tmp = BN_CTX_get(ctx);
175
if (dh->priv_key == NULL)
177
DHerr(DH_F_DH_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE);
180
if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P))
182
if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
183
if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p,
184
dh->p,ctx)) goto err;
187
mont=(BN_MONT_CTX *)dh->method_mont_p;
188
if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key,dh->p,ctx,mont))
190
DHerr(DH_F_DH_COMPUTE_KEY,ERR_R_BN_LIB);
194
ret=BN_bn2bin(tmp,key);
201
static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
202
const BIGNUM *a, const BIGNUM *p,
203
const BIGNUM *m, BN_CTX *ctx,
208
BN_ULONG A = a->d[0];
209
return BN_mod_exp_mont_word(r,A,p,m,ctx,m_ctx);
212
return BN_mod_exp_mont(r,a,p,m,ctx,m_ctx);
216
static int dh_init(DH *dh)
218
dh->flags |= DH_FLAG_CACHE_MONT_P;
222
static int dh_finish(DH *dh)
224
if(dh->method_mont_p)
225
BN_MONT_CTX_free((BN_MONT_CTX *)dh->method_mont_p);