1/*
2 * Copyright (c) 2018 Thomas Pornin <pornin@bolet.org>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22 * SOFTWARE.
23 */
24
25#include "inner.h"
26
27static const unsigned char POINT_LEN[] = {
28	  0,   /* 0: not a valid curve ID */
29	 43,   /* sect163k1 */
30	 43,   /* sect163r1 */
31	 43,   /* sect163r2 */
32	 51,   /* sect193r1 */
33	 51,   /* sect193r2 */
34	 61,   /* sect233k1 */
35	 61,   /* sect233r1 */
36	 61,   /* sect239k1 */
37	 73,   /* sect283k1 */
38	 73,   /* sect283r1 */
39	105,   /* sect409k1 */
40	105,   /* sect409r1 */
41	145,   /* sect571k1 */
42	145,   /* sect571r1 */
43	 41,   /* secp160k1 */
44	 41,   /* secp160r1 */
45	 41,   /* secp160r2 */
46	 49,   /* secp192k1 */
47	 49,   /* secp192r1 */
48	 57,   /* secp224k1 */
49	 57,   /* secp224r1 */
50	 65,   /* secp256k1 */
51	 65,   /* secp256r1 */
52	 97,   /* secp384r1 */
53	133,   /* secp521r1 */
54	 65,   /* brainpoolP256r1 */
55	 97,   /* brainpoolP384r1 */
56	129,   /* brainpoolP512r1 */
57	 32,   /* curve25519 */
58	 56,   /* curve448 */
59};
60
61/* see bearssl_ec.h */
62size_t
63br_ec_compute_pub(const br_ec_impl *impl, br_ec_public_key *pk,
64	void *kbuf, const br_ec_private_key *sk)
65{
66	int curve;
67	size_t len;
68
69	curve = sk->curve;
70	if (curve < 0 || curve >= 32 || curve >= (int)(sizeof POINT_LEN)
71		|| ((impl->supported_curves >> curve) & 1) == 0)
72	{
73		return 0;
74	}
75	if (kbuf == NULL) {
76		return POINT_LEN[curve];
77	}
78	len = impl->mulgen(kbuf, sk->x, sk->xlen, curve);
79	if (pk != NULL) {
80		pk->curve = curve;
81		pk->q = kbuf;
82		pk->qlen = len;
83	}
84	return len;
85}
86