curve25519.h

 1/* SPDX-License-Identifier: GPL-2.0 OR MIT */
 2/*
 3 * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
 4 */
 5
 6#ifndef CURVE25519_H
 7#define CURVE25519_H
 8
 9#include <linux/types.h>
10#include <linux/random.h>
11
12enum curve25519_lengths {
13	CURVE25519_KEY_SIZE = 32
14};
15
16void curve25519_generic(u8 out[at_least CURVE25519_KEY_SIZE],
17			const u8 scalar[at_least CURVE25519_KEY_SIZE],
18			const u8 point[at_least CURVE25519_KEY_SIZE]);
19
20bool __must_check
21curve25519(u8 mypublic[at_least CURVE25519_KEY_SIZE],
22	   const u8 secret[at_least CURVE25519_KEY_SIZE],
23	   const u8 basepoint[at_least CURVE25519_KEY_SIZE]);
24
25bool __must_check
26curve25519_generate_public(u8 pub[at_least CURVE25519_KEY_SIZE],
27			   const u8 secret[at_least CURVE25519_KEY_SIZE]);
28
29static inline void
30curve25519_clamp_secret(u8 secret[at_least CURVE25519_KEY_SIZE])
31{
32	secret[0] &= 248;
33	secret[31] = (secret[31] & 127) | 64;
34}
35
36static inline void
37curve25519_generate_secret(u8 secret[at_least CURVE25519_KEY_SIZE])
38{
39	get_random_bytes_wait(secret, CURVE25519_KEY_SIZE);
40	curve25519_clamp_secret(secret);
41}
42
43#endif /* CURVE25519_H */