mirror of
https://github.com/ClassiCube/ClassiCube.git
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107 lines
3.0 KiB
C
107 lines
3.0 KiB
C
/*
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* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include "inner.h"
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/* see bearssl_block.h */
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uint32_t
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br_chacha20_ct_run(const void *key,
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const void *iv, uint32_t cc, void *data, size_t len)
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{
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unsigned char *buf;
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uint32_t kw[8], ivw[3];
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size_t u;
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static const uint32_t CW[] = {
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0x61707865, 0x3320646e, 0x79622d32, 0x6b206574
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};
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buf = data;
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for (u = 0; u < 8; u ++) {
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kw[u] = br_dec32le((const unsigned char *)key + (u << 2));
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}
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for (u = 0; u < 3; u ++) {
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ivw[u] = br_dec32le((const unsigned char *)iv + (u << 2));
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}
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while (len > 0) {
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uint32_t state[16];
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int i;
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size_t clen;
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unsigned char tmp[64];
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br_memcpy(&state[0], CW, sizeof CW);
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br_memcpy(&state[4], kw, sizeof kw);
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state[12] = cc;
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br_memcpy(&state[13], ivw, sizeof ivw);
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for (i = 0; i < 10; i ++) {
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#define QROUND(a, b, c, d) do { \
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state[a] += state[b]; \
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state[d] ^= state[a]; \
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state[d] = (state[d] << 16) | (state[d] >> 16); \
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state[c] += state[d]; \
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state[b] ^= state[c]; \
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state[b] = (state[b] << 12) | (state[b] >> 20); \
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state[a] += state[b]; \
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state[d] ^= state[a]; \
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state[d] = (state[d] << 8) | (state[d] >> 24); \
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state[c] += state[d]; \
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state[b] ^= state[c]; \
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state[b] = (state[b] << 7) | (state[b] >> 25); \
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} while (0)
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QROUND( 0, 4, 8, 12);
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QROUND( 1, 5, 9, 13);
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QROUND( 2, 6, 10, 14);
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QROUND( 3, 7, 11, 15);
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QROUND( 0, 5, 10, 15);
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QROUND( 1, 6, 11, 12);
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QROUND( 2, 7, 8, 13);
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QROUND( 3, 4, 9, 14);
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#undef QROUND
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}
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for (u = 0; u < 4; u ++) {
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br_enc32le(&tmp[u << 2], state[u] + CW[u]);
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}
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for (u = 4; u < 12; u ++) {
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br_enc32le(&tmp[u << 2], state[u] + kw[u - 4]);
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}
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br_enc32le(&tmp[48], state[12] + cc);
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for (u = 13; u < 16; u ++) {
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br_enc32le(&tmp[u << 2], state[u] + ivw[u - 13]);
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}
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clen = len < 64 ? len : 64;
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for (u = 0; u < clen; u ++) {
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buf[u] ^= tmp[u];
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}
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buf += clen;
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len -= clen;
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cc ++;
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}
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return cc;
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}
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