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  
27  static 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 */
62  size_t
63  br_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  }