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 /* see inner.h */ 28 void 29 br_mgf1_xor(void *data, size_t len, 30 const br_hash_class *dig, const void *seed, size_t seed_len) 31 { 32 unsigned char *buf; 33 size_t u, hlen; 34 uint32_t c; 35 36 buf = data; 37 hlen = br_digest_size(dig); 38 for (u = 0, c = 0; u < len; u += hlen, c ++) { 39 br_hash_compat_context hc; 40 unsigned char tmp[64]; 41 size_t v; 42 43 hc.vtable = dig; 44 dig->init(&hc.vtable); 45 dig->update(&hc.vtable, seed, seed_len); 46 br_enc32be(tmp, c); 47 dig->update(&hc.vtable, tmp, 4); 48 dig->out(&hc.vtable, tmp); 49 for (v = 0; v < hlen; v ++) { 50 if ((u + v) >= len) { 51 break; 52 } 53 buf[u + v] ^= tmp[v]; 54 } 55 } 56 } 57