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d02b48c6 | 1 | /* crypto/dh/dh_key.c */ |
58964a49 | 2 | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
d02b48c6 RE |
3 | * All rights reserved. |
4 | * | |
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. | |
8 | * | |
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). | |
15 | * | |
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. | |
22 | * | |
23 | * Redistribution and use in source and binary forms, with or without | |
24 | * modification, are permitted provided that the following conditions | |
25 | * are met: | |
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)" | |
40 | * | |
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 | |
51 | * SUCH DAMAGE. | |
52 | * | |
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.] | |
57 | */ | |
58 | ||
59 | #include <stdio.h> | |
60 | #include "cryptlib.h" | |
61 | #include "bn.h" | |
62 | #include "rand.h" | |
63 | #include "dh.h" | |
64 | ||
6b691a5c | 65 | int DH_generate_key(DH *dh) |
d02b48c6 RE |
66 | { |
67 | int ok=0; | |
68 | unsigned int i; | |
dfeab068 RE |
69 | BN_CTX ctx; |
70 | BN_MONT_CTX *mont; | |
d02b48c6 RE |
71 | BIGNUM *pub_key=NULL,*priv_key=NULL; |
72 | ||
dfeab068 | 73 | BN_CTX_init(&ctx); |
d02b48c6 RE |
74 | |
75 | if (dh->priv_key == NULL) | |
76 | { | |
77 | i=dh->length; | |
78 | if (i == 0) | |
79 | { | |
80 | /* Make the number p-1 bits long */ | |
81 | i=BN_num_bits(dh->p)-1; | |
82 | } | |
83 | priv_key=BN_new(); | |
84 | if (priv_key == NULL) goto err; | |
85 | if (!BN_rand(priv_key,i,0,0)) goto err; | |
86 | } | |
87 | else | |
88 | priv_key=dh->priv_key; | |
89 | ||
90 | if (dh->pub_key == NULL) | |
91 | { | |
92 | pub_key=BN_new(); | |
93 | if (pub_key == NULL) goto err; | |
94 | } | |
95 | else | |
96 | pub_key=dh->pub_key; | |
97 | ||
dfeab068 RE |
98 | if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P)) |
99 | { | |
100 | if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL) | |
101 | if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p, | |
102 | dh->p,&ctx)) goto err; | |
103 | } | |
104 | mont=(BN_MONT_CTX *)dh->method_mont_p; | |
105 | ||
106 | if (!BN_mod_exp_mont(pub_key,dh->g,priv_key,dh->p,&ctx,mont)) goto err; | |
d02b48c6 RE |
107 | |
108 | dh->pub_key=pub_key; | |
109 | dh->priv_key=priv_key; | |
110 | ok=1; | |
111 | err: | |
112 | if (ok != 1) | |
113 | DHerr(DH_F_DH_GENERATE_KEY,ERR_R_BN_LIB); | |
114 | ||
115 | if ((pub_key != NULL) && (dh->pub_key == NULL)) BN_free(pub_key); | |
116 | if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key); | |
dfeab068 | 117 | BN_CTX_free(&ctx); |
d02b48c6 RE |
118 | return(ok); |
119 | } | |
120 | ||
6b691a5c | 121 | int DH_compute_key(unsigned char *key, BIGNUM *pub_key, DH *dh) |
d02b48c6 | 122 | { |
dfeab068 RE |
123 | BN_CTX ctx; |
124 | BN_MONT_CTX *mont; | |
d02b48c6 RE |
125 | BIGNUM *tmp; |
126 | int ret= -1; | |
127 | ||
dfeab068 RE |
128 | BN_CTX_init(&ctx); |
129 | tmp= &(ctx.bn[ctx.tos++]); | |
d02b48c6 RE |
130 | |
131 | if (dh->priv_key == NULL) | |
132 | { | |
133 | DHerr(DH_F_DH_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE); | |
134 | goto err; | |
135 | } | |
dfeab068 RE |
136 | if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P)) |
137 | { | |
138 | if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL) | |
139 | if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p, | |
140 | dh->p,&ctx)) goto err; | |
141 | } | |
142 | ||
143 | mont=(BN_MONT_CTX *)dh->method_mont_p; | |
144 | if (!BN_mod_exp_mont(tmp,pub_key,dh->priv_key,dh->p,&ctx,mont)) | |
d02b48c6 RE |
145 | { |
146 | DHerr(DH_F_DH_COMPUTE_KEY,ERR_R_BN_LIB); | |
147 | goto err; | |
148 | } | |
149 | ||
150 | ret=BN_bn2bin(tmp,key); | |
151 | err: | |
dfeab068 | 152 | BN_CTX_free(&ctx); |
d02b48c6 RE |
153 | return(ret); |
154 | } |