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authorryker <>1998-10-05 20:13:14 +0000
committerryker <>1998-10-05 20:13:14 +0000
commitaeeae06a79815dc190061534d47236cec09f9e32 (patch)
tree851692b9c2f9c04f077666855641900f19fdb217 /src/lib/libcrypto/dh/dh_gen.c
parenta4f79641824cbf9f60ca9d1168d1fcc46717a82a (diff)
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Import of SSLeay-0.9.0b with RSA and IDEA stubbed + OpenBSD build
functionality for shared libs. Note that routines such as sslv2_init and friends that use RSA will not work due to lack of RSA in this library. Needs documentation and help from ports for easy upgrade to full functionality where legally possible.
Diffstat (limited to 'src/lib/libcrypto/dh/dh_gen.c')
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diff --git a/src/lib/libcrypto/dh/dh_gen.c b/src/lib/libcrypto/dh/dh_gen.c
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1/* crypto/dh/dh_gen.c */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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 "dh.h"
63
64/* We generate DH parameters as follows
65 * find a prime q which is prime_len/2 bits long.
66 * p=(2*q)+1 or (p-1)/2 = q
67 * For this case, g is a generator if
68 * g^((p-1)/q) mod p != 1 for values of q which are the factors of p-1.
69 * Since the factors of p-1 are q and 2, we just need to check
70 * g^2 mod p != 1 and g^q mod p != 1.
71 *
72 * Having said all that,
73 * there is another special case method for the generators 2, 3 and 5.
74 * for 2, p mod 24 == 11
75 * for 3, p mod 12 == 5 <<<<< does not work for strong primes.
76 * for 5, p mod 10 == 3 or 7
77 *
78 * Thanks to Phil Karn <karn@qualcomm.com> for the pointers about the
79 * special generators and for answering some of my questions.
80 *
81 * I've implemented the second simple method :-).
82 * Since DH should be using a strong prime (both p and q are prime),
83 * this generator function can take a very very long time to run.
84 */
85
86DH *DH_generate_parameters(prime_len,generator,callback,cb_arg)
87int prime_len;
88int generator;
89void (*callback)(P_I_I_P);
90char *cb_arg;
91 {
92 BIGNUM *p=NULL,*t1,*t2;
93 DH *ret=NULL;
94 int g,ok= -1;
95 BN_CTX *ctx=NULL;
96
97 ret=DH_new();
98 ctx=BN_CTX_new();
99 if (ctx == NULL) goto err;
100 t1=ctx->bn[0];
101 t2=ctx->bn[1];
102 ctx->tos=2;
103
104 if (generator == DH_GENERATOR_2)
105 {
106 BN_set_word(t1,24);
107 BN_set_word(t2,11);
108 g=2;
109 }
110#ifdef undef /* does not work for strong primes */
111 else if (generator == DH_GENERATOR_3)
112 {
113 BN_set_word(t1,12);
114 BN_set_word(t2,5);
115 g=3;
116 }
117#endif
118 else if (generator == DH_GENERATOR_5)
119 {
120 BN_set_word(t1,10);
121 BN_set_word(t2,3);
122 /* BN_set_word(t3,7); just have to miss
123 * out on these ones :-( */
124 g=5;
125 }
126 else
127 g=generator;
128
129 p=BN_generate_prime(prime_len,1,t1,t2,callback,cb_arg);
130 if (p == NULL) goto err;
131 if (callback != NULL) callback(3,0,cb_arg);
132 ret->p=p;
133 ret->g=BN_new();
134 if (!BN_set_word(ret->g,g)) goto err;
135 ok=1;
136err:
137 if (ok == -1)
138 {
139 DHerr(DH_F_DH_GENERATE_PARAMETERS,ERR_R_BN_LIB);
140 ok=0;
141 }
142
143 if (ctx != NULL) BN_CTX_free(ctx);
144 if (!ok && (ret != NULL))
145 {
146 DH_free(ret);
147 ret=NULL;
148 }
149 return(ret);
150 }