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87 lines
2.2 KiB
C
87 lines
2.2 KiB
C
/*
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* Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the OpenSSL license (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#include <openssl/rc4.h>
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#include "rc4_locl.h"
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/*-
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* RC4 as implemented from a posting from
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* Newsgroups: sci.crypt
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* From: sterndark@netcom.com (David Sterndark)
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* Subject: RC4 Algorithm revealed.
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* Message-ID: <sternCvKL4B.Hyy@netcom.com>
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* Date: Wed, 14 Sep 1994 06:35:31 GMT
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*/
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void RC4(RC4_KEY *key, size_t len, const unsigned char *indata,
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unsigned char *outdata)
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{
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register RC4_INT *d;
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register RC4_INT x, y, tx, ty;
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size_t i;
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x = key->x;
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y = key->y;
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d = key->data;
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#define LOOP(in,out) \
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x=((x+1)&0xff); \
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tx=d[x]; \
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y=(tx+y)&0xff; \
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d[x]=ty=d[y]; \
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d[y]=tx; \
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(out) = d[(tx+ty)&0xff]^ (in);
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i = len >> 3;
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if (i) {
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for (;;) {
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LOOP(indata[0], outdata[0]);
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LOOP(indata[1], outdata[1]);
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LOOP(indata[2], outdata[2]);
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LOOP(indata[3], outdata[3]);
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LOOP(indata[4], outdata[4]);
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LOOP(indata[5], outdata[5]);
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LOOP(indata[6], outdata[6]);
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LOOP(indata[7], outdata[7]);
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indata += 8;
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outdata += 8;
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if (--i == 0)
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break;
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}
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}
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i = len & 0x07;
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if (i) {
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for (;;) {
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LOOP(indata[0], outdata[0]);
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if (--i == 0)
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break;
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LOOP(indata[1], outdata[1]);
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if (--i == 0)
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break;
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LOOP(indata[2], outdata[2]);
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if (--i == 0)
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break;
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LOOP(indata[3], outdata[3]);
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if (--i == 0)
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break;
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LOOP(indata[4], outdata[4]);
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if (--i == 0)
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break;
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LOOP(indata[5], outdata[5]);
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if (--i == 0)
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break;
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LOOP(indata[6], outdata[6]);
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if (--i == 0)
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break;
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}
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}
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key->x = x;
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key->y = y;
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}
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