crypto/include/internal/ec_int.h

   1 /*
   2  * Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (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 HEADER_OSSL_EC_INTERNAL_H
  13 # define HEADER_OSSL_EC_INTERNAL_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  */
  47 int 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