1 /* crypto/ecdh/ech_ossl.c */
2 /* ====================================================================
3 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
5 * The Elliptic Curve Public-Key Crypto Library (ECC Code) included
6 * herein is developed by SUN MICROSYSTEMS, INC., and is contributed
7 * to the OpenSSL project.
9 * The ECC Code is licensed pursuant to the OpenSSL open source
10 * license provided below.
12 * The ECDH software is originally written by Douglas Stebila of
13 * Sun Microsystems Laboratories.
16 /* ====================================================================
17 * Copyright (c) 1998-2003 The OpenSSL Project. All rights reserved.
19 * Redistribution and use in source and binary forms, with or without
20 * modification, are permitted provided that the following conditions
23 * 1. Redistributions of source code must retain the above copyright
24 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in
28 * the documentation and/or other materials provided with the
31 * 3. All advertising materials mentioning features or use of this
32 * software must display the following acknowledgment:
33 * "This product includes software developed by the OpenSSL Project
34 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
36 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
37 * endorse or promote products derived from this software without
38 * prior written permission. For written permission, please contact
39 * openssl-core@OpenSSL.org.
41 * 5. Products derived from this software may not be called "OpenSSL"
42 * nor may "OpenSSL" appear in their names without prior written
43 * permission of the OpenSSL Project.
45 * 6. Redistributions of any form whatsoever must retain the following
47 * "This product includes software developed by the OpenSSL Project
48 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
50 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
51 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
53 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
54 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
55 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
56 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
57 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
58 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
59 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
60 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
61 * OF THE POSSIBILITY OF SUCH DAMAGE.
62 * ====================================================================
64 * This product includes cryptographic software written by Eric Young
65 * (eay@cryptsoft.com). This product includes software written by Tim
66 * Hudson (tjh@cryptsoft.com).
76 #include <openssl/err.h>
77 #include <openssl/sha.h>
78 #include <openssl/obj_mac.h>
79 #include <openssl/bn.h>
81 static int ecdh_compute_key(void *out, size_t len, const EC_POINT *pub_key,
83 void *(*KDF) (const void *in, size_t inlen,
84 void *out, size_t *outlen));
86 static ECDH_METHOD openssl_ecdh_meth = {
87 "OpenSSL ECDH method",
97 const ECDH_METHOD *ECDH_OpenSSL(void)
99 return &openssl_ecdh_meth;
103 * This implementation is based on the following primitives in the IEEE 1363 standard:
106 * Finally an optional KDF is applied.
108 static int ecdh_compute_key(void *out, size_t outlen, const EC_POINT *pub_key,
110 void *(*KDF) (const void *in, size_t inlen,
111 void *out, size_t *outlen))
114 EC_POINT *tmp = NULL;
115 BIGNUM *x = NULL, *y = NULL;
116 const BIGNUM *priv_key;
117 const EC_GROUP *group;
120 unsigned char *buf = NULL;
122 if (outlen > INT_MAX) {
123 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ERR_R_MALLOC_FAILURE); /* sort of,
128 if ((ctx = BN_CTX_new()) == NULL)
134 priv_key = EC_KEY_get0_private_key(ecdh);
135 if (priv_key == NULL) {
136 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ECDH_R_NO_PRIVATE_VALUE);
140 group = EC_KEY_get0_group(ecdh);
142 if (EC_KEY_get_flags(ecdh) & EC_FLAG_COFACTOR_ECDH) {
143 if (!EC_GROUP_get_cofactor(group, x, ctx) ||
144 !BN_mul(x, x, priv_key, ctx)) {
145 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ERR_R_MALLOC_FAILURE);
151 if ((tmp = EC_POINT_new(group)) == NULL) {
152 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ERR_R_MALLOC_FAILURE);
156 if (!EC_POINT_mul(group, tmp, NULL, pub_key, priv_key, ctx)) {
157 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ECDH_R_POINT_ARITHMETIC_FAILURE);
161 if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) ==
162 NID_X9_62_prime_field) {
163 if (!EC_POINT_get_affine_coordinates_GFp(group, tmp, x, y, ctx)) {
164 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ECDH_R_POINT_ARITHMETIC_FAILURE);
168 #ifndef OPENSSL_NO_EC2M
170 if (!EC_POINT_get_affine_coordinates_GF2m(group, tmp, x, y, ctx)) {
171 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ECDH_R_POINT_ARITHMETIC_FAILURE);
177 buflen = (EC_GROUP_get_degree(group) + 7) / 8;
178 len = BN_num_bytes(x);
180 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ERR_R_INTERNAL_ERROR);
183 if ((buf = OPENSSL_malloc(buflen)) == NULL) {
184 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ERR_R_MALLOC_FAILURE);
188 memset(buf, 0, buflen - len);
189 if (len != (size_t)BN_bn2bin(x, buf + buflen - len)) {
190 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ERR_R_BN_LIB);
195 if (KDF(buf, buflen, out, &outlen) == NULL) {
196 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY, ECDH_R_KDF_FAILED);
201 /* no KDF, just copy as much as we can */
204 memcpy(out, buf, outlen);
216 OPENSSL_cleanse(buf, buflen);