1/*
2 * Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the OpenSSL license (the "License").  You may not use
5 * this file except in compliance with the License.  You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10/* Internal EC functions for other submodules: not for application use */
11
12#ifndef OSSL_CRYPTO_EC_H
13# define OSSL_CRYPTO_EC_H
14# include <openssl/opensslconf.h>
15
16# ifndef OPENSSL_NO_EC
17
18#  include <openssl/ec.h>
19
20/*-
21 * Computes the multiplicative inverse of x in the range
22 * [1,EC_GROUP::order), where EC_GROUP::order is the cardinality of the
23 * subgroup generated by the generator G:
24 *
25 *         res := x^(-1) (mod EC_GROUP::order).
26 *
27 * This function expects the following two conditions to hold:
28 *  - the EC_GROUP order is prime, and
29 *  - x is included in the range [1, EC_GROUP::order).
30 *
31 * This function returns 1 on success, 0 on error.
32 *
33 * If the EC_GROUP order is even, this function explicitly returns 0 as
34 * an error.
35 * In case any of the two conditions stated above is not satisfied,
36 * the correctness of its output is not guaranteed, even if the return
37 * value could still be 1 (as primality testing and a conditional modular
38 * reduction round on the input can be omitted by the underlying
39 * implementations for better SCA properties on regular input values).
40 */
41__owur int ec_group_do_inverse_ord(const EC_GROUP *group, BIGNUM *res,
42                                   const BIGNUM *x, BN_CTX *ctx);
43
44/*-
45 * ECDH Key Derivation Function as defined in ANSI X9.63
46 */
47int ecdh_KDF_X9_63(unsigned char *out, size_t outlen,
48                   const unsigned char *Z, size_t Zlen,
49                   const unsigned char *sinfo, size_t sinfolen,
50                   const EVP_MD *md);
51
52# endif /* OPENSSL_NO_EC */
53#endif
54