| 1/* $OpenBSD: dh.c,v 1.42 2006/08/03 03:34:42 deraadt Exp $ */
|
1/*
2 * Copyright (c) 2000 Niels Provos. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#include "includes.h"
| 2/*
3 * Copyright (c) 2000 Niels Provos. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "includes.h"
|
26RCSID("$OpenBSD: dh.c,v 1.31 2004/08/04 10:37:52 djm Exp $");
| |
27
| 27
|
28#include "xmalloc.h"
| 28#include <sys/param.h>
|
29
30#include <openssl/bn.h>
31#include <openssl/dh.h>
| 29
30#include <openssl/bn.h>
31#include <openssl/dh.h>
|
32#include <openssl/evp.h>
| |
33
| 32
|
34#include "buffer.h"
35#include "cipher.h"
36#include "kex.h"
| 33#include <stdarg.h>
34#include <stdio.h>
35#include <stdlib.h>
36#include <string.h>
37
|
37#include "dh.h"
38#include "pathnames.h"
39#include "log.h"
40#include "misc.h"
41
42static int
43parse_prime(int linenum, char *line, struct dhgroup *dhg)
44{
45 char *cp, *arg;
46 char *strsize, *gen, *prime;
| 38#include "dh.h"
39#include "pathnames.h"
40#include "log.h"
41#include "misc.h"
42
43static int
44parse_prime(int linenum, char *line, struct dhgroup *dhg)
45{
46 char *cp, *arg;
47 char *strsize, *gen, *prime;
|
| 48 const char *errstr = NULL;
|
47
48 cp = line;
| 49
50 cp = line;
|
49 arg = strdelim(&cp);
| 51 if ((arg = strdelim(&cp)) == NULL)
52 return 0;
|
50 /* Ignore leading whitespace */
51 if (*arg == '\0')
52 arg = strdelim(&cp);
53 if (!arg || !*arg || *arg == '#')
54 return 0;
55
56 /* time */
57 if (cp == NULL || *arg == '\0')
58 goto fail;
59 arg = strsep(&cp, " "); /* type */
60 if (cp == NULL || *arg == '\0')
61 goto fail;
62 arg = strsep(&cp, " "); /* tests */
63 if (cp == NULL || *arg == '\0')
64 goto fail;
65 arg = strsep(&cp, " "); /* tries */
66 if (cp == NULL || *arg == '\0')
67 goto fail;
68 strsize = strsep(&cp, " "); /* size */
69 if (cp == NULL || *strsize == '\0' ||
| 53 /* Ignore leading whitespace */
54 if (*arg == '\0')
55 arg = strdelim(&cp);
56 if (!arg || !*arg || *arg == '#')
57 return 0;
58
59 /* time */
60 if (cp == NULL || *arg == '\0')
61 goto fail;
62 arg = strsep(&cp, " "); /* type */
63 if (cp == NULL || *arg == '\0')
64 goto fail;
65 arg = strsep(&cp, " "); /* tests */
66 if (cp == NULL || *arg == '\0')
67 goto fail;
68 arg = strsep(&cp, " "); /* tries */
69 if (cp == NULL || *arg == '\0')
70 goto fail;
71 strsize = strsep(&cp, " "); /* size */
72 if (cp == NULL || *strsize == '\0' ||
|
70 (dhg->size = atoi(strsize)) == 0)
| 73 (dhg->size = (u_int)strtonum(strsize, 0, 64*1024, &errstr)) == 0 ||
74 errstr)
|
71 goto fail;
72 /* The whole group is one bit larger */
73 dhg->size++;
74 gen = strsep(&cp, " "); /* gen */
75 if (cp == NULL || *gen == '\0')
76 goto fail;
77 prime = strsep(&cp, " "); /* prime */
78 if (cp != NULL || *prime == '\0')
79 goto fail;
80
81 if ((dhg->g = BN_new()) == NULL)
82 fatal("parse_prime: BN_new failed");
83 if ((dhg->p = BN_new()) == NULL)
84 fatal("parse_prime: BN_new failed");
85 if (BN_hex2bn(&dhg->g, gen) == 0)
86 goto failclean;
87
88 if (BN_hex2bn(&dhg->p, prime) == 0)
89 goto failclean;
90
91 if (BN_num_bits(dhg->p) != dhg->size)
92 goto failclean;
93
94 if (BN_is_zero(dhg->g) || BN_is_one(dhg->g))
95 goto failclean;
96
97 return (1);
98
99 failclean:
100 BN_clear_free(dhg->g);
101 BN_clear_free(dhg->p);
102 fail:
103 error("Bad prime description in line %d", linenum);
104 return (0);
105}
106
107DH *
108choose_dh(int min, int wantbits, int max)
109{
110 FILE *f;
111 char line[4096];
112 int best, bestcount, which;
113 int linenum;
114 struct dhgroup dhg;
115
116 if ((f = fopen(_PATH_DH_MODULI, "r")) == NULL &&
117 (f = fopen(_PATH_DH_PRIMES, "r")) == NULL) {
118 logit("WARNING: %s does not exist, using fixed modulus",
119 _PATH_DH_MODULI);
120 return (dh_new_group14());
121 }
122
123 linenum = 0;
124 best = bestcount = 0;
125 while (fgets(line, sizeof(line), f)) {
126 linenum++;
127 if (!parse_prime(linenum, line, &dhg))
128 continue;
129 BN_clear_free(dhg.g);
130 BN_clear_free(dhg.p);
131
132 if (dhg.size > max || dhg.size < min)
133 continue;
134
135 if ((dhg.size > wantbits && dhg.size < best) ||
136 (dhg.size > best && best < wantbits)) {
137 best = dhg.size;
138 bestcount = 0;
139 }
140 if (dhg.size == best)
141 bestcount++;
142 }
143 rewind(f);
144
145 if (bestcount == 0) {
146 fclose(f);
147 logit("WARNING: no suitable primes in %s", _PATH_DH_PRIMES);
148 return (dh_new_group14());
149 }
150
151 linenum = 0;
152 which = arc4random() % bestcount;
153 while (fgets(line, sizeof(line), f)) {
154 if (!parse_prime(linenum, line, &dhg))
155 continue;
156 if ((dhg.size > max || dhg.size < min) ||
157 dhg.size != best ||
158 linenum++ != which) {
159 BN_clear_free(dhg.g);
160 BN_clear_free(dhg.p);
161 continue;
162 }
163 break;
164 }
165 fclose(f);
166 if (linenum != which+1)
167 fatal("WARNING: line %d disappeared in %s, giving up",
168 which, _PATH_DH_PRIMES);
169
170 return (dh_new_group(dhg.g, dhg.p));
171}
172
173/* diffie-hellman-groupN-sha1 */
174
175int
176dh_pub_is_valid(DH *dh, BIGNUM *dh_pub)
177{
178 int i;
179 int n = BN_num_bits(dh_pub);
180 int bits_set = 0;
| 75 goto fail;
76 /* The whole group is one bit larger */
77 dhg->size++;
78 gen = strsep(&cp, " "); /* gen */
79 if (cp == NULL || *gen == '\0')
80 goto fail;
81 prime = strsep(&cp, " "); /* prime */
82 if (cp != NULL || *prime == '\0')
83 goto fail;
84
85 if ((dhg->g = BN_new()) == NULL)
86 fatal("parse_prime: BN_new failed");
87 if ((dhg->p = BN_new()) == NULL)
88 fatal("parse_prime: BN_new failed");
89 if (BN_hex2bn(&dhg->g, gen) == 0)
90 goto failclean;
91
92 if (BN_hex2bn(&dhg->p, prime) == 0)
93 goto failclean;
94
95 if (BN_num_bits(dhg->p) != dhg->size)
96 goto failclean;
97
98 if (BN_is_zero(dhg->g) || BN_is_one(dhg->g))
99 goto failclean;
100
101 return (1);
102
103 failclean:
104 BN_clear_free(dhg->g);
105 BN_clear_free(dhg->p);
106 fail:
107 error("Bad prime description in line %d", linenum);
108 return (0);
109}
110
111DH *
112choose_dh(int min, int wantbits, int max)
113{
114 FILE *f;
115 char line[4096];
116 int best, bestcount, which;
117 int linenum;
118 struct dhgroup dhg;
119
120 if ((f = fopen(_PATH_DH_MODULI, "r")) == NULL &&
121 (f = fopen(_PATH_DH_PRIMES, "r")) == NULL) {
122 logit("WARNING: %s does not exist, using fixed modulus",
123 _PATH_DH_MODULI);
124 return (dh_new_group14());
125 }
126
127 linenum = 0;
128 best = bestcount = 0;
129 while (fgets(line, sizeof(line), f)) {
130 linenum++;
131 if (!parse_prime(linenum, line, &dhg))
132 continue;
133 BN_clear_free(dhg.g);
134 BN_clear_free(dhg.p);
135
136 if (dhg.size > max || dhg.size < min)
137 continue;
138
139 if ((dhg.size > wantbits && dhg.size < best) ||
140 (dhg.size > best && best < wantbits)) {
141 best = dhg.size;
142 bestcount = 0;
143 }
144 if (dhg.size == best)
145 bestcount++;
146 }
147 rewind(f);
148
149 if (bestcount == 0) {
150 fclose(f);
151 logit("WARNING: no suitable primes in %s", _PATH_DH_PRIMES);
152 return (dh_new_group14());
153 }
154
155 linenum = 0;
156 which = arc4random() % bestcount;
157 while (fgets(line, sizeof(line), f)) {
158 if (!parse_prime(linenum, line, &dhg))
159 continue;
160 if ((dhg.size > max || dhg.size < min) ||
161 dhg.size != best ||
162 linenum++ != which) {
163 BN_clear_free(dhg.g);
164 BN_clear_free(dhg.p);
165 continue;
166 }
167 break;
168 }
169 fclose(f);
170 if (linenum != which+1)
171 fatal("WARNING: line %d disappeared in %s, giving up",
172 which, _PATH_DH_PRIMES);
173
174 return (dh_new_group(dhg.g, dhg.p));
175}
176
177/* diffie-hellman-groupN-sha1 */
178
179int
180dh_pub_is_valid(DH *dh, BIGNUM *dh_pub)
181{
182 int i;
183 int n = BN_num_bits(dh_pub);
184 int bits_set = 0;
|
| 185 BIGNUM *tmp;
|
181
182 if (dh_pub->neg) {
183 logit("invalid public DH value: negativ");
184 return 0;
185 }
| 186
187 if (dh_pub->neg) {
188 logit("invalid public DH value: negativ");
189 return 0;
190 }
|
| 191 if (BN_cmp(dh_pub, BN_value_one()) != 1) { /* pub_exp <= 1 */
192 logit("invalid public DH value: <= 1");
193 return 0;
194 }
195
196 if ((tmp = BN_new()) == NULL)
197 return (-1);
198 if (!BN_sub(tmp, dh->p, BN_value_one()) ||
199 BN_cmp(dh_pub, tmp) != -1) { /* pub_exp > p-2 */
200 BN_clear_free(tmp);
201 logit("invalid public DH value: >= p-1");
202 return 0;
203 }
204 BN_clear_free(tmp);
205
|
186 for (i = 0; i <= n; i++)
187 if (BN_is_bit_set(dh_pub, i))
188 bits_set++;
189 debug2("bits set: %d/%d", bits_set, BN_num_bits(dh->p));
190
191 /* if g==2 and bits_set==1 then computing log_g(dh_pub) is trivial */
| 206 for (i = 0; i <= n; i++)
207 if (BN_is_bit_set(dh_pub, i))
208 bits_set++;
209 debug2("bits set: %d/%d", bits_set, BN_num_bits(dh->p));
210
211 /* if g==2 and bits_set==1 then computing log_g(dh_pub) is trivial */
|
192 if (bits_set > 1 && (BN_cmp(dh_pub, dh->p) == -1))
| 212 if (bits_set > 1)
|
193 return 1;
| 213 return 1;
|
| 214
|
194 logit("invalid public DH value (%d/%d)", bits_set, BN_num_bits(dh->p));
195 return 0;
196}
197
198void
199dh_gen_key(DH *dh, int need)
200{
201 int i, bits_set, tries = 0;
202
203 if (dh->p == NULL)
204 fatal("dh_gen_key: dh->p == NULL");
205 if (need > INT_MAX / 2 || 2 * need >= BN_num_bits(dh->p))
206 fatal("dh_gen_key: group too small: %d (2*need %d)",
207 BN_num_bits(dh->p), 2*need);
208 do {
209 if (dh->priv_key != NULL)
210 BN_clear_free(dh->priv_key);
211 if ((dh->priv_key = BN_new()) == NULL)
212 fatal("dh_gen_key: BN_new failed");
213 /* generate a 2*need bits random private exponent */
214 if (!BN_rand(dh->priv_key, 2*need, 0, 0))
215 fatal("dh_gen_key: BN_rand failed");
216 if (DH_generate_key(dh) == 0)
217 fatal("DH_generate_key");
218 for (i = 0, bits_set = 0; i <= BN_num_bits(dh->priv_key); i++)
219 if (BN_is_bit_set(dh->priv_key, i))
220 bits_set++;
221 debug2("dh_gen_key: priv key bits set: %d/%d",
222 bits_set, BN_num_bits(dh->priv_key));
223 if (tries++ > 10)
224 fatal("dh_gen_key: too many bad keys: giving up");
225 } while (!dh_pub_is_valid(dh, dh->pub_key));
226}
227
228DH *
229dh_new_group_asc(const char *gen, const char *modulus)
230{
231 DH *dh;
232
233 if ((dh = DH_new()) == NULL)
234 fatal("dh_new_group_asc: DH_new");
235
236 if (BN_hex2bn(&dh->p, modulus) == 0)
237 fatal("BN_hex2bn p");
238 if (BN_hex2bn(&dh->g, gen) == 0)
239 fatal("BN_hex2bn g");
240
241 return (dh);
242}
243
244/*
245 * This just returns the group, we still need to generate the exchange
246 * value.
247 */
248
249DH *
250dh_new_group(BIGNUM *gen, BIGNUM *modulus)
251{
252 DH *dh;
253
254 if ((dh = DH_new()) == NULL)
255 fatal("dh_new_group: DH_new");
256 dh->p = modulus;
257 dh->g = gen;
258
259 return (dh);
260}
261
262DH *
263dh_new_group1(void)
264{
265 static char *gen = "2", *group1 =
266 "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
267 "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
268 "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
269 "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
270 "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE65381"
271 "FFFFFFFF" "FFFFFFFF";
272
273 return (dh_new_group_asc(gen, group1));
274}
275
276DH *
277dh_new_group14(void)
278{
279 static char *gen = "2", *group14 =
280 "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
281 "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
282 "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
283 "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
284 "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE45B3D"
285 "C2007CB8" "A163BF05" "98DA4836" "1C55D39A" "69163FA8" "FD24CF5F"
286 "83655D23" "DCA3AD96" "1C62F356" "208552BB" "9ED52907" "7096966D"
287 "670C354E" "4ABC9804" "F1746C08" "CA18217C" "32905E46" "2E36CE3B"
288 "E39E772C" "180E8603" "9B2783A2" "EC07A28F" "B5C55DF0" "6F4C52C9"
289 "DE2BCBF6" "95581718" "3995497C" "EA956AE5" "15D22618" "98FA0510"
290 "15728E5A" "8AACAA68" "FFFFFFFF" "FFFFFFFF";
291
292 return (dh_new_group_asc(gen, group14));
293}
294
295/*
296 * Estimates the group order for a Diffie-Hellman group that has an
297 * attack complexity approximately the same as O(2**bits). Estimate
298 * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3)))
299 */
300
301int
302dh_estimate(int bits)
303{
304
305 if (bits <= 128)
306 return (1024); /* O(2**86) */
307 if (bits <= 192)
308 return (2048); /* O(2**116) */
309 return (4096); /* O(2**156) */
310}
| 215 logit("invalid public DH value (%d/%d)", bits_set, BN_num_bits(dh->p));
216 return 0;
217}
218
219void
220dh_gen_key(DH *dh, int need)
221{
222 int i, bits_set, tries = 0;
223
224 if (dh->p == NULL)
225 fatal("dh_gen_key: dh->p == NULL");
226 if (need > INT_MAX / 2 || 2 * need >= BN_num_bits(dh->p))
227 fatal("dh_gen_key: group too small: %d (2*need %d)",
228 BN_num_bits(dh->p), 2*need);
229 do {
230 if (dh->priv_key != NULL)
231 BN_clear_free(dh->priv_key);
232 if ((dh->priv_key = BN_new()) == NULL)
233 fatal("dh_gen_key: BN_new failed");
234 /* generate a 2*need bits random private exponent */
235 if (!BN_rand(dh->priv_key, 2*need, 0, 0))
236 fatal("dh_gen_key: BN_rand failed");
237 if (DH_generate_key(dh) == 0)
238 fatal("DH_generate_key");
239 for (i = 0, bits_set = 0; i <= BN_num_bits(dh->priv_key); i++)
240 if (BN_is_bit_set(dh->priv_key, i))
241 bits_set++;
242 debug2("dh_gen_key: priv key bits set: %d/%d",
243 bits_set, BN_num_bits(dh->priv_key));
244 if (tries++ > 10)
245 fatal("dh_gen_key: too many bad keys: giving up");
246 } while (!dh_pub_is_valid(dh, dh->pub_key));
247}
248
249DH *
250dh_new_group_asc(const char *gen, const char *modulus)
251{
252 DH *dh;
253
254 if ((dh = DH_new()) == NULL)
255 fatal("dh_new_group_asc: DH_new");
256
257 if (BN_hex2bn(&dh->p, modulus) == 0)
258 fatal("BN_hex2bn p");
259 if (BN_hex2bn(&dh->g, gen) == 0)
260 fatal("BN_hex2bn g");
261
262 return (dh);
263}
264
265/*
266 * This just returns the group, we still need to generate the exchange
267 * value.
268 */
269
270DH *
271dh_new_group(BIGNUM *gen, BIGNUM *modulus)
272{
273 DH *dh;
274
275 if ((dh = DH_new()) == NULL)
276 fatal("dh_new_group: DH_new");
277 dh->p = modulus;
278 dh->g = gen;
279
280 return (dh);
281}
282
283DH *
284dh_new_group1(void)
285{
286 static char *gen = "2", *group1 =
287 "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
288 "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
289 "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
290 "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
291 "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE65381"
292 "FFFFFFFF" "FFFFFFFF";
293
294 return (dh_new_group_asc(gen, group1));
295}
296
297DH *
298dh_new_group14(void)
299{
300 static char *gen = "2", *group14 =
301 "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
302 "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
303 "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
304 "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
305 "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE45B3D"
306 "C2007CB8" "A163BF05" "98DA4836" "1C55D39A" "69163FA8" "FD24CF5F"
307 "83655D23" "DCA3AD96" "1C62F356" "208552BB" "9ED52907" "7096966D"
308 "670C354E" "4ABC9804" "F1746C08" "CA18217C" "32905E46" "2E36CE3B"
309 "E39E772C" "180E8603" "9B2783A2" "EC07A28F" "B5C55DF0" "6F4C52C9"
310 "DE2BCBF6" "95581718" "3995497C" "EA956AE5" "15D22618" "98FA0510"
311 "15728E5A" "8AACAA68" "FFFFFFFF" "FFFFFFFF";
312
313 return (dh_new_group_asc(gen, group14));
314}
315
316/*
317 * Estimates the group order for a Diffie-Hellman group that has an
318 * attack complexity approximately the same as O(2**bits). Estimate
319 * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3)))
320 */
321
322int
323dh_estimate(int bits)
324{
325
326 if (bits <= 128)
327 return (1024); /* O(2**86) */
328 if (bits <= 192)
329 return (2048); /* O(2**116) */
330 return (4096); /* O(2**156) */
331}
|