57 lines
1.7 KiB
C

/*
* Copyright (c) 2018 Thomas Pornin <pornin@bolet.org>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "inner.h"
/* see inner.h */
void
br_mgf1_xor(void *data, size_t len,
const br_hash_class *dig, const void *seed, size_t seed_len)
{
unsigned char *buf;
size_t u, hlen;
uint32_t c;
buf = data;
hlen = br_digest_size(dig);
for (u = 0, c = 0; u < len; u += hlen, c ++) {
br_hash_compat_context hc;
unsigned char tmp[64];
size_t v;
hc.vtable = dig;
dig->init(&hc.vtable);
dig->update(&hc.vtable, seed, seed_len);
br_enc32be(tmp, c);
dig->update(&hc.vtable, tmp, 4);
dig->out(&hc.vtable, tmp);
for (v = 0; v < hlen; v ++) {
if ((u + v) >= len) {
break;
}
buf[u + v] ^= tmp[v];
}
}
}