1 /* $OpenBSD: curve25519.h,v 1.2 2020/07/22 13:54:30 tobhe Exp $ */ 2 /* 3 * Copyright (C) 2019-2020 Matt Dunwoodie <ncon@noconroy.net> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #ifndef _CURVE25519_H_ 19 #define _CURVE25519_H_ 20 21 #include <sys/libkern.h> /* karc4random_buf() */ 22 23 #define CURVE25519_KEY_SIZE 32 24 25 int curve25519(uint8_t out[CURVE25519_KEY_SIZE], 26 const uint8_t scalar[CURVE25519_KEY_SIZE], 27 const uint8_t point[CURVE25519_KEY_SIZE]); 28 29 int curve25519_generate_public(uint8_t pub[CURVE25519_KEY_SIZE], 30 const uint8_t secret[CURVE25519_KEY_SIZE]); 31 32 static inline void 33 curve25519_clamp_secret(uint8_t secret[CURVE25519_KEY_SIZE]) 34 { 35 secret[0] &= 248; 36 secret[31] = (secret[31] & 127) | 64; 37 } 38 39 static inline void 40 curve25519_generate_secret(uint8_t secret[CURVE25519_KEY_SIZE]) 41 { 42 karc4random_buf(secret, CURVE25519_KEY_SIZE); 43 curve25519_clamp_secret(secret); 44 } 45 46 #endif /* _CURVE25519_H_ */ 47