1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2021 The FreeBSD Foundation
5 *
6 * This software was developed by Ararat River Consulting, LLC under
7 * sponsorship from the FreeBSD Foundation.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#ifndef __CRYPTO_CURVE25519_H__
32#define	__CRYPTO_CURVE25519_H__
33
34#include <sys/libkern.h>
35
36#define	CURVE25519_KEY_SIZE	32
37
38bool	curve25519(uint8_t *public, const uint8_t *secret,
39    const uint8_t *basepoint);
40bool	curve25519_generate_public(uint8_t *public,
41    const uint8_t *secret);
42
43static __inline void
44curve25519_clamp_secret(uint8_t *secret)
45{
46	secret[0] &= 248;
47	secret[31] &= 127;
48	secret[31] |= 64;
49}
50
51static __inline void
52curve25519_generate_secret(uint8_t *secret)
53{
54	arc4random_buf(secret, CURVE25519_KEY_SIZE);
55	curve25519_clamp_secret(secret);
56}
57
58#endif /* __CRYPTO_CURVE25519_H__ */
59