1 /* crypto/srp/srp_lib.c */
3 * Written by Christophe Renou (christophe.renou@edelweb.fr) with the
4 * precious help of Peter Sylvester (peter.sylvester@edelweb.fr) for the
5 * EdelKey project and contributed to the OpenSSL project 2004.
7 /* ====================================================================
8 * Copyright (c) 2004 The OpenSSL Project. All rights reserved.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in
19 * the documentation and/or other materials provided with the
22 * 3. All advertising materials mentioning features or use of this
23 * software must display the following acknowledgment:
24 * "This product includes software developed by the OpenSSL Project
25 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
27 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
28 * endorse or promote products derived from this software without
29 * prior written permission. For written permission, please contact
30 * licensing@OpenSSL.org.
32 * 5. Products derived from this software may not be called "OpenSSL"
33 * nor may "OpenSSL" appear in their names without prior written
34 * permission of the OpenSSL Project.
36 * 6. Redistributions of any form whatsoever must retain the following
38 * "This product includes software developed by the OpenSSL Project
39 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
41 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
42 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
44 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
45 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
46 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
47 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
48 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
49 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
50 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
51 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
52 * OF THE POSSIBILITY OF SUCH DAMAGE.
53 * ====================================================================
55 * This product includes cryptographic software written by Eric Young
56 * (eay@cryptsoft.com). This product includes software written by Tim
57 * Hudson (tjh@cryptsoft.com).
60 #ifndef OPENSSL_NO_SRP
61 # include "internal/cryptlib.h"
62 # include <openssl/sha.h>
63 # include <openssl/srp.h>
64 # include <openssl/evp.h>
65 # include "internal/bn_srp.h"
67 static BIGNUM *srp_Calc_k(BIGNUM *N, BIGNUM *g)
69 /* k = SHA1(N | PAD(g)) -- tls-srp draft 8 */
71 unsigned char digest[SHA_DIGEST_LENGTH];
73 EVP_MD_CTX *ctxt = NULL;
75 int longN = BN_num_bytes(N);
78 if (BN_ucmp(g, N) >= 0)
81 ctxt = EVP_MD_CTX_new();
84 if ((tmp = OPENSSL_malloc(longN)) == NULL)
88 EVP_DigestInit_ex(ctxt, EVP_sha1(), NULL);
89 EVP_DigestUpdate(ctxt, tmp, longN);
91 memset(tmp, 0, longN);
92 longg = BN_bn2bin(g, tmp);
93 /* use the zeros behind to pad on left */
94 EVP_DigestUpdate(ctxt, tmp + longg, longN - longg);
95 EVP_DigestUpdate(ctxt, tmp, longg);
98 EVP_DigestFinal_ex(ctxt, digest, NULL);
99 res = BN_bin2bn(digest, sizeof(digest), NULL);
101 EVP_MD_CTX_free(ctxt);
105 BIGNUM *SRP_Calc_u(BIGNUM *A, BIGNUM *B, BIGNUM *N)
107 /* k = SHA1(PAD(A) || PAD(B) ) -- tls-srp draft 8 */
110 unsigned char cu[SHA_DIGEST_LENGTH];
112 EVP_MD_CTX *ctxt = NULL;
114 if ((A == NULL) || (B == NULL) || (N == NULL))
117 if (BN_ucmp(A, N) >= 0 || BN_ucmp(B, N) >= 0)
120 longN = BN_num_bytes(N);
122 ctxt = EVP_MD_CTX_new();
125 if ((cAB = OPENSSL_malloc(2 * longN)) == NULL)
128 memset(cAB, 0, longN);
130 EVP_DigestInit_ex(ctxt, EVP_sha1(), NULL);
131 EVP_DigestUpdate(ctxt, cAB + BN_bn2bin(A, cAB + longN), longN);
132 EVP_DigestUpdate(ctxt, cAB + BN_bn2bin(B, cAB + longN), longN);
134 EVP_DigestFinal_ex(ctxt, cu, NULL);
136 if ((u = BN_bin2bn(cu, sizeof(cu), NULL)) == NULL)
143 EVP_MD_CTX_free(ctxt);
148 BIGNUM *SRP_Calc_server_key(BIGNUM *A, BIGNUM *v, BIGNUM *u, BIGNUM *b,
151 BIGNUM *tmp = NULL, *S = NULL;
154 if (u == NULL || A == NULL || v == NULL || b == NULL || N == NULL)
157 if ((bn_ctx = BN_CTX_new()) == NULL ||
158 (tmp = BN_new()) == NULL || (S = BN_new()) == NULL)
161 /* S = (A*v**u) ** b */
163 if (!BN_mod_exp(tmp, v, u, N, bn_ctx))
165 if (!BN_mod_mul(tmp, A, tmp, N, bn_ctx))
167 if (!BN_mod_exp(S, tmp, b, N, bn_ctx))
175 BIGNUM *SRP_Calc_B(BIGNUM *b, BIGNUM *N, BIGNUM *g, BIGNUM *v)
177 BIGNUM *kv = NULL, *gb = NULL;
178 BIGNUM *B = NULL, *k = NULL;
181 if (b == NULL || N == NULL || g == NULL || v == NULL ||
182 (bn_ctx = BN_CTX_new()) == NULL)
185 if ((kv = BN_new()) == NULL ||
186 (gb = BN_new()) == NULL || (B = BN_new()) == NULL)
191 if (!BN_mod_exp(gb, g, b, N, bn_ctx)
192 || (k = srp_Calc_k(N, g)) == NULL
193 || !BN_mod_mul(kv, v, k, N, bn_ctx)
194 || !BN_mod_add(B, gb, kv, N, bn_ctx)) {
206 BIGNUM *SRP_Calc_x(BIGNUM *s, const char *user, const char *pass)
208 unsigned char dig[SHA_DIGEST_LENGTH];
213 if ((s == NULL) || (user == NULL) || (pass == NULL))
216 ctxt = EVP_MD_CTX_new();
219 if ((cs = OPENSSL_malloc(BN_num_bytes(s))) == NULL)
222 EVP_DigestInit_ex(ctxt, EVP_sha1(), NULL);
223 EVP_DigestUpdate(ctxt, user, strlen(user));
224 EVP_DigestUpdate(ctxt, ":", 1);
225 EVP_DigestUpdate(ctxt, pass, strlen(pass));
226 EVP_DigestFinal_ex(ctxt, dig, NULL);
228 EVP_DigestInit_ex(ctxt, EVP_sha1(), NULL);
230 EVP_DigestUpdate(ctxt, cs, BN_num_bytes(s));
232 EVP_DigestUpdate(ctxt, dig, sizeof(dig));
233 EVP_DigestFinal_ex(ctxt, dig, NULL);
235 res = BN_bin2bn(dig, sizeof(dig), NULL);
237 EVP_MD_CTX_free(ctxt);
241 BIGNUM *SRP_Calc_A(BIGNUM *a, BIGNUM *N, BIGNUM *g)
246 if (a == NULL || N == NULL || g == NULL || (bn_ctx = BN_CTX_new()) == NULL)
249 if ((A = BN_new()) != NULL && !BN_mod_exp(A, g, a, N, bn_ctx)) {
257 BIGNUM *SRP_Calc_client_key(BIGNUM *N, BIGNUM *B, BIGNUM *g, BIGNUM *x,
258 BIGNUM *a, BIGNUM *u)
260 BIGNUM *tmp = NULL, *tmp2 = NULL, *tmp3 = NULL, *k = NULL, *K = NULL;
263 if (u == NULL || B == NULL || N == NULL || g == NULL || x == NULL
264 || a == NULL || (bn_ctx = BN_CTX_new()) == NULL)
267 if ((tmp = BN_new()) == NULL ||
268 (tmp2 = BN_new()) == NULL ||
269 (tmp3 = BN_new()) == NULL ||
270 (K = BN_new()) == NULL)
273 if (!BN_mod_exp(tmp, g, x, N, bn_ctx))
275 if ((k = srp_Calc_k(N, g)) == NULL)
277 if (!BN_mod_mul(tmp2, tmp, k, N, bn_ctx))
279 if (!BN_mod_sub(tmp, B, tmp2, N, bn_ctx))
281 if (!BN_mod_mul(tmp3, u, x, N, bn_ctx))
283 if (!BN_mod_add(tmp2, a, tmp3, N, bn_ctx))
285 if (!BN_mod_exp(K, tmp, tmp2, N, bn_ctx))
297 int SRP_Verify_B_mod_N(BIGNUM *B, BIGNUM *N)
303 if (B == NULL || N == NULL || (bn_ctx = BN_CTX_new()) == NULL)
306 if ((r = BN_new()) == NULL)
308 /* Checks if B % N == 0 */
309 if (!BN_nnmod(r, B, N, bn_ctx))
311 ret = !BN_is_zero(r);
318 int SRP_Verify_A_mod_N(BIGNUM *A, BIGNUM *N)
320 /* Checks if A % N == 0 */
321 return SRP_Verify_B_mod_N(A, N);
324 static SRP_gN knowngN[] = {
325 {"8192", (BIGNUM *)&bn_generator_19, (BIGNUM *)&bn_group_8192},
326 {"6144", (BIGNUM *)&bn_generator_5, (BIGNUM *)&bn_group_6144},
327 {"4096", (BIGNUM *)&bn_generator_5, (BIGNUM *)&bn_group_4096},
328 {"3072", (BIGNUM *)&bn_generator_5, (BIGNUM *)&bn_group_3072},
329 {"2048", (BIGNUM *)&bn_generator_2, (BIGNUM *)&bn_group_2048},
330 {"1536", (BIGNUM *)&bn_generator_2, (BIGNUM *)&bn_group_1536},
331 {"1024", (BIGNUM *)&bn_generator_2, (BIGNUM *)&bn_group_1024},
334 # define KNOWN_GN_NUMBER sizeof(knowngN) / sizeof(SRP_gN)
337 * Check if G and N are kwown parameters. The values have been generated
338 * from the ietf-tls-srp draft version 8
340 char *SRP_check_known_gN_param(BIGNUM *g, BIGNUM *N)
343 if ((g == NULL) || (N == NULL))
346 for (i = 0; i < KNOWN_GN_NUMBER; i++) {
347 if (BN_cmp(knowngN[i].g, g) == 0 && BN_cmp(knowngN[i].N, N) == 0)
348 return knowngN[i].id;
353 SRP_gN *SRP_get_default_gN(const char *id)
359 for (i = 0; i < KNOWN_GN_NUMBER; i++) {
360 if (strcmp(knowngN[i].id, id) == 0)