2 * Copyright (c) 2018 Thomas Pornin <pornin@bolet.org>
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:
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
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
27 /* see bearssl_ec.h */
29 br_ec_keygen(const br_prng_class
**rng_ctx
,
30 const br_ec_impl
*impl
, br_ec_private_key
*sk
,
31 void *kbuf
, int curve
)
33 const unsigned char *order
;
38 if (curve
< 0 || curve
>= 32
39 || ((impl
->supported_curves
>> curve
) & 1) == 0)
43 order
= impl
->order(curve
, &len
);
44 while (len
> 0 && *order
== 0) {
48 if (kbuf
== NULL
|| len
== 0) {
57 * We generate sequences of random bits of the right size, until
58 * the value is strictly lower than the curve order (we also
59 * check for all-zero values, which are invalid).
66 (*rng_ctx
)->generate(rng_ctx
, buf
, len
);
72 cc
= ((unsigned)(buf
[u
] - order
[u
] - cc
) >> 8) & 1;
75 if (cc
!= 0 && zz
!= 0) {