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/ecdh.h>
77 #include <openssl/err.h>
78 #include <openssl/sha.h>
79 #include <openssl/obj_mac.h>
80 #include <openssl/bn.h>
82 static int ecdh_compute_key(void *out, size_t len, const EC_POINT *pub_key, EC_KEY *ecdh,
83 void *(*KDF)(void *in, size_t inlen, void *out, size_t outlen));
85 static ECDH_METHOD openssl_ecdh_meth = {
86 "OpenSSL ECDH method",
96 const ECDH_METHOD *ECDH_OpenSSL(void)
98 return &openssl_ecdh_meth;
102 /* This implementation is based on the following primitives in the IEEE 1363 standard:
105 * Finally an optional KDF is applied.
107 static int ecdh_compute_key(void *out, size_t outlen, const EC_POINT *pub_key, EC_KEY *ecdh,
108 void *(*KDF)(void *in, size_t inlen, void *out, size_t outlen))
112 BIGNUM *x=NULL, *y=NULL;
115 unsigned char *buf=NULL;
117 if (outlen > INT_MAX)
119 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ERR_R_MALLOC_FAILURE); /* sort of, anyway */
123 if ((ctx = BN_CTX_new()) == NULL) goto err;
128 if (ecdh->priv_key == NULL)
130 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ECDH_R_NO_PRIVATE_VALUE);
134 if ((tmp=EC_POINT_new(ecdh->group)) == NULL)
136 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ERR_R_MALLOC_FAILURE);
140 if (!EC_POINT_mul(ecdh->group, tmp, NULL, pub_key, ecdh->priv_key, ctx))
142 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ECDH_R_POINT_ARITHMETIC_FAILURE);
146 if (EC_METHOD_get_field_type(EC_GROUP_method_of(ecdh->group)) == NID_X9_62_prime_field)
148 if (!EC_POINT_get_affine_coordinates_GFp(ecdh->group, tmp, x, y, ctx))
150 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ECDH_R_POINT_ARITHMETIC_FAILURE);
156 if (!EC_POINT_get_affine_coordinates_GF2m(ecdh->group, tmp, x, y, ctx))
158 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ECDH_R_POINT_ARITHMETIC_FAILURE);
163 buflen = (EC_GROUP_get_degree(ecdh->group) + 7)/8;
164 len = BN_num_bytes(x);
167 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ERR_R_INTERNAL_ERROR);
170 if ((buf = OPENSSL_malloc(buflen)) == NULL)
172 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ERR_R_MALLOC_FAILURE);
176 memset(buf, 0, buflen - len);
177 if (len != (size_t)BN_bn2bin(x, buf + buflen - len))
179 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ERR_R_BN_LIB);
185 if (KDF(buf, buflen, out, outlen) == NULL)
187 ECDHerr(ECDH_F_ECDH_COMPUTE_KEY,ECDH_R_KDF_FAILED);
194 /* no KDF, just copy as much as we can */
197 memcpy(out, buf, outlen);
202 if (tmp) EC_POINT_free(tmp);
203 if (ctx) BN_CTX_end(ctx);
204 if (ctx) BN_CTX_free(ctx);
205 if (buf) OPENSSL_free(buf);