1 /* $OpenBSD: dh.c,v 1.9 2004/04/15 18:39:25 deraadt Exp $ */
2 /* $EOM: dh.c,v 1.5 1999/04/17 23:20:22 niklas Exp $ */
5 * Copyright (c) 1998 Niels Provos. All rights reserved.
6 * Copyright (c) 1999 Niklas Hallqvist. All rights reserved.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 * This code was written under funding by Ericsson Radio Systems.
33 #include <sys/param.h>
37 #include "math_group.h"
42 * Returns the length of our exchange value.
46 dh_getlen(struct group
*group
)
48 return group
->getlen(group
);
52 * Creates the exchange value we are offering to the other party.
53 * Each time this function is called a new value is created, that
54 * means the application has to save the exchange value itself,
55 * dh_create_exchange should only be called once.
58 dh_create_exchange(struct group
*group
, u_int8_t
*buf
)
60 if (group
->setrandom(group
, group
->c
))
62 if (group
->operation(group
, group
->a
, group
->gen
, group
->c
))
64 group
->getraw(group
, group
->a
, buf
);
69 * Creates the Diffie-Hellman shared secret in 'secret', where 'exchange'
70 * is the exchange value offered by the other party. No length verification
71 * is done for the value, the application has to do that.
74 dh_create_shared(struct group
*group
, u_int8_t
*secret
, u_int8_t
*exchange
)
76 if (group
->setraw(group
, group
->b
, exchange
, group
->getlen(group
)))
78 if (group
->operation(group
, group
->a
, group
->b
, group
->c
))
80 group
->getraw(group
, group
->a
, secret
);