| 1 | /*
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| 2 | * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
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| 3 | *
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| 4 | * Licensed under the OpenSSL license (the "License"). You may not use
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| 5 | * this file except in compliance with the License. You can obtain a copy
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| 6 | * in the file LICENSE in the source distribution or at
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| 7 | * https://www.openssl.org/source/license.html
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| 8 | */
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| 9 |
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| 10 | #include <openssl/rc4.h>
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| 11 | #include "rc4_local.h"
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| 12 |
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| 13 | /*-
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| 14 | * RC4 as implemented from a posting from
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| 15 | * Newsgroups: sci.crypt
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| 16 | * Subject: RC4 Algorithm revealed.
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| 17 | * Message-ID: <[email protected]>
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| 18 | * Date: Wed, 14 Sep 1994 06:35:31 GMT
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| 19 | */
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| 20 |
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| 21 | void RC4(RC4_KEY *key, size_t len, const unsigned char *indata,
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| 22 | unsigned char *outdata)
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| 23 | {
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| 24 | register RC4_INT *d;
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| 25 | register RC4_INT x, y, tx, ty;
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| 26 | size_t i;
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| 27 |
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| 28 | x = key->x;
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| 29 | y = key->y;
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| 30 | d = key->data;
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| 31 |
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| 32 | #define LOOP(in,out) \
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| 33 | x=((x+1)&0xff); \
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| 34 | tx=d[x]; \
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| 35 | y=(tx+y)&0xff; \
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| 36 | d[x]=ty=d[y]; \
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| 37 | d[y]=tx; \
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| 38 | (out) = d[(tx+ty)&0xff]^ (in);
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| 39 |
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| 40 | i = len >> 3;
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| 41 | if (i) {
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| 42 | for (;;) {
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| 43 | LOOP(indata[0], outdata[0]);
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| 44 | LOOP(indata[1], outdata[1]);
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| 45 | LOOP(indata[2], outdata[2]);
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| 46 | LOOP(indata[3], outdata[3]);
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| 47 | LOOP(indata[4], outdata[4]);
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| 48 | LOOP(indata[5], outdata[5]);
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| 49 | LOOP(indata[6], outdata[6]);
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| 50 | LOOP(indata[7], outdata[7]);
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| 51 | indata += 8;
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| 52 | outdata += 8;
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| 53 | if (--i == 0)
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| 54 | break;
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| 55 | }
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| 56 | }
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| 57 | i = len & 0x07;
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| 58 | if (i) {
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| 59 | for (;;) {
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| 60 | LOOP(indata[0], outdata[0]);
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| 61 | if (--i == 0)
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| 62 | break;
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| 63 | LOOP(indata[1], outdata[1]);
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| 64 | if (--i == 0)
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| 65 | break;
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| 66 | LOOP(indata[2], outdata[2]);
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| 67 | if (--i == 0)
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| 68 | break;
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| 69 | LOOP(indata[3], outdata[3]);
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| 70 | if (--i == 0)
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| 71 | break;
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| 72 | LOOP(indata[4], outdata[4]);
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| 73 | if (--i == 0)
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| 74 | break;
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| 75 | LOOP(indata[5], outdata[5]);
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| 76 | if (--i == 0)
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| 77 | break;
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| 78 | LOOP(indata[6], outdata[6]);
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| 79 | if (--i == 0)
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| 80 | break;
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| 81 | }
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| 82 | }
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| 83 | key->x = x;
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| 84 | key->y = y;
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| 85 | }
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