ecdh.h

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/* ====================================================================
 * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
 *
 * The Elliptic Curve Public-Key Crypto Library (ECC Code) included
 * herein is developed by SUN MICROSYSTEMS, INC., and is contributed
 * to the OpenSSL project.
 *
 * The ECC Code is licensed pursuant to the OpenSSL open source
 * license provided below.
 *
 * The ECDH software is originally written by Douglas Stebila of
 * Sun Microsystems Laboratories.
 *
 */
/* ====================================================================
 * Copyright (c) 2000-2002 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
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 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
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 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com). */

#ifndef OPENSSL_HEADER_ECDH_H
#define OPENSSL_HEADER_ECDH_H

#include <openssl/base.h>

#include <openssl/ec_key.h>

#if defined(__cplusplus)
extern "C" {
#endif


/* Elliptic curve Diffie-Hellman. */


/* ECDH_compute_key calculates the shared key between |pub_key| and |priv_key|.
 * If |kdf| is not NULL, then it is called with the bytes of the shared key and
 * the parameter |out|. When |kdf| returns, the value of |*outlen| becomes the
 * return value. Otherwise, as many bytes of the shared key as will fit are
 * copied directly to, at most, |outlen| bytes at |out|. It returns the number
 * of bytes written to |out|, or -1 on error. */
OPENSSL_EXPORT int ECDH_compute_key(
    void *out, size_t outlen, const EC_POINT *pub_key, const EC_KEY *priv_key,
    void *(*kdf)(const void *in, size_t inlen, void *out, size_t *outlen));


#if defined(__cplusplus)
}  /* extern C */
#endif

#define ECDH_R_KDF_FAILED 100
#define ECDH_R_NO_PRIVATE_VALUE 101
#define ECDH_R_POINT_ARITHMETIC_FAILURE 102

#endif  /* OPENSSL_HEADER_ECDH_H */