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66 lines
1.9 KiB
C
66 lines
1.9 KiB
C
/*
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* MIT License
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*
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* Copyright (c) 2020 Ozan Tezcan
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* 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, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN 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 "sc_rc4.h"
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#include <memory.h>
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void sc_rc4_init(struct sc_rc4 *rc4, const unsigned char rand[256])
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{
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unsigned char t;
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rc4->j = 0;
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rc4->i = 0;
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memcpy(rc4->s, rand, 256);
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for (int i = 0; i < 256; i++) {
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rc4->j += rc4->s[i] + rand[i];
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t = rc4->s[rc4->j];
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rc4->s[rc4->j] = rc4->s[i];
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rc4->s[i] = t;
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}
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}
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void sc_rc4_random(struct sc_rc4 *rc4, void *buf, int size)
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{
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unsigned char t;
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unsigned char *p = buf;
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if (size <= 0 || buf == NULL) {
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return;
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}
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do {
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rc4->i++;
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t = rc4->s[rc4->i];
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rc4->j += t;
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rc4->s[rc4->i] = rc4->s[rc4->j];
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rc4->s[rc4->j] = t;
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t += rc4->s[rc4->i];
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*(p++) = rc4->s[t];
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} while (--size);
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}
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