254 lines
8.5 KiB
C
254 lines
8.5 KiB
C
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/* $OpenBSD: rc4_enc.c,v 1.16 2017/08/13 17:46:24 bcook Exp $ */
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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* All rights reserved.
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*
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* This package is an SSL implementation written
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* by Eric Young (eay@cryptsoft.com).
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* The implementation was written so as to conform with Netscapes SSL.
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*
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* This library is free for commercial and non-commercial use as long as
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* the following conditions are aheared to. The following conditions
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* apply to all code found in this distribution, be it the RC4, RSA,
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* lhash, DES, etc., code; not just the SSL code. The SSL documentation
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* included with this distribution is covered by the same copyright terms
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* except that the holder is Tim Hudson (tjh@cryptsoft.com).
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*
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* Copyright remains Eric Young's, and as such any Copyright notices in
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* the code are not to be removed.
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* If this package is used in a product, Eric Young should be given attribution
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* as the author of the parts of the library used.
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* This can be in the form of a textual message at program startup or
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* in documentation (online or textual) provided with the package.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* "This product includes cryptographic software written by
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* Eric Young (eay@cryptsoft.com)"
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* The word 'cryptographic' can be left out if the rouines from the library
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* being used are not cryptographic related :-).
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* 4. If you include any Windows specific code (or a derivative thereof) from
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* the apps directory (application code) you must include an acknowledgement:
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
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*
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* The licence and distribution terms for any publically available version or
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* derivative of this code cannot be changed. i.e. this code cannot simply be
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* copied and put under another distribution licence
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* [including the GNU Public Licence.]
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*/
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#include <machine/endian.h>
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#include <openssl/rc4.h>
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#include "rc4_locl.h"
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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
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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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RC4_INT *d;
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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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#if defined(RC4_CHUNK)
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/*
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* The original reason for implementing this(*) was the fact that
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* pre-21164a Alpha CPUs don't have byte load/store instructions
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* and e.g. a byte store has to be done with 64-bit load, shift,
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* and, or and finally 64-bit store. Peaking data and operating
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* at natural word size made it possible to reduce amount of
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* instructions as well as to perform early read-ahead without
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* suffering from RAW (read-after-write) hazard. This resulted
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* in ~40%(**) performance improvement on 21064 box with gcc.
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* But it's not only Alpha users who win here:-) Thanks to the
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* early-n-wide read-ahead this implementation also exhibits
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* >40% speed-up on SPARC and 20-30% on 64-bit MIPS (depending
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* on sizeof(RC4_INT)).
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*
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* (*) "this" means code which recognizes the case when input
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* and output pointers appear to be aligned at natural CPU
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* word boundary
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* (**) i.e. according to 'apps/openssl speed rc4' benchmark,
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* crypto/rc4/rc4speed.c exhibits almost 70% speed-up...
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*
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* Caveats.
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*
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* - RC4_CHUNK="unsigned long long" should be a #1 choice for
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* UltraSPARC. Unfortunately gcc generates very slow code
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* (2.5-3 times slower than one generated by Sun's WorkShop
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* C) and therefore gcc (at least 2.95 and earlier) should
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* always be told that RC4_CHUNK="unsigned long".
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*
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* <appro@fy.chalmers.se>
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*/
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# define RC4_STEP ( \
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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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ty=d[y], \
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d[y]=tx, \
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d[x]=ty, \
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(RC4_CHUNK)d[(tx+ty)&0xff]\
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)
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if ((((size_t)indata & (sizeof(RC4_CHUNK) - 1)) |
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((size_t)outdata & (sizeof(RC4_CHUNK) - 1))) == 0 ) {
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RC4_CHUNK ichunk, otp;
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/*
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* I reckon we can afford to implement both endian
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* cases and to decide which way to take at run-time
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* because the machine code appears to be very compact
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* and redundant 1-2KB is perfectly tolerable (i.e.
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* in case the compiler fails to eliminate it:-). By
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* suggestion from Terrel Larson <terr@terralogic.net>.
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*
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* Special notes.
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*
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* - compilers (those I've tried) don't seem to have
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* problems eliminating either the operators guarded
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* by "if (sizeof(RC4_CHUNK)==8)" or the condition
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* expressions themselves so I've got 'em to replace
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* corresponding #ifdefs from the previous version;
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* - I chose to let the redundant switch cases when
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* sizeof(RC4_CHUNK)!=8 be (were also #ifdefed
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* before);
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* - in case you wonder "&(sizeof(RC4_CHUNK)*8-1)" in
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* [LB]ESHFT guards against "shift is out of range"
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* warnings when sizeof(RC4_CHUNK)!=8
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*
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* <appro@fy.chalmers.se>
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*/
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#if BYTE_ORDER == BIG_ENDIAN
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# define BESHFT(c) (((sizeof(RC4_CHUNK)-(c)-1)*8)&(sizeof(RC4_CHUNK)*8-1))
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for (; len & (0 - sizeof(RC4_CHUNK)); len -= sizeof(RC4_CHUNK)) {
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ichunk = *(RC4_CHUNK *)indata;
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otp = RC4_STEP << BESHFT(0);
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otp |= RC4_STEP << BESHFT(1);
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otp |= RC4_STEP << BESHFT(2);
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otp |= RC4_STEP << BESHFT(3);
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if (sizeof(RC4_CHUNK) == 8) {
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otp |= RC4_STEP << BESHFT(4);
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otp |= RC4_STEP << BESHFT(5);
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otp |= RC4_STEP << BESHFT(6);
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otp |= RC4_STEP << BESHFT(7);
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}
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*(RC4_CHUNK *)outdata = otp^ichunk;
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indata += sizeof(RC4_CHUNK);
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outdata += sizeof(RC4_CHUNK);
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}
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#else
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# define LESHFT(c) (((c)*8)&(sizeof(RC4_CHUNK)*8-1))
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for (; len & (0 - sizeof(RC4_CHUNK)); len -= sizeof(RC4_CHUNK)) {
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ichunk = *(RC4_CHUNK *)indata;
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otp = RC4_STEP;
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otp |= RC4_STEP << 8;
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otp |= RC4_STEP << 16;
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otp |= RC4_STEP << 24;
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if (sizeof(RC4_CHUNK) == 8) {
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otp |= RC4_STEP << LESHFT(4);
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otp |= RC4_STEP << LESHFT(5);
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otp |= RC4_STEP << LESHFT(6);
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otp |= RC4_STEP << LESHFT(7);
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}
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*(RC4_CHUNK *)outdata = otp ^ ichunk;
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indata += sizeof(RC4_CHUNK);
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outdata += sizeof(RC4_CHUNK);
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}
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#endif
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}
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#endif
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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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#ifndef RC4_INDEX
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#define RC4_LOOP(a,b,i) LOOP(*((a)++),*((b)++))
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#else
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#define RC4_LOOP(a,b,i) LOOP(a[i],b[i])
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#endif
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i = len >> 3;
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if (i) {
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for (;;) {
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RC4_LOOP(indata, outdata, 0);
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RC4_LOOP(indata, outdata, 1);
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RC4_LOOP(indata, outdata, 2);
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RC4_LOOP(indata, outdata, 3);
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RC4_LOOP(indata, outdata, 4);
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RC4_LOOP(indata, outdata, 5);
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RC4_LOOP(indata, outdata, 6);
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RC4_LOOP(indata, outdata, 7);
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#ifdef RC4_INDEX
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indata += 8;
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outdata += 8;
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#endif
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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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RC4_LOOP(indata, outdata, 0);
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if (--i == 0)
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break;
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RC4_LOOP(indata, outdata, 1);
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if (--i == 0)
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break;
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RC4_LOOP(indata, outdata, 2);
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if (--i == 0)
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break;
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RC4_LOOP(indata, outdata, 3);
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if (--i == 0)
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break;
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RC4_LOOP(indata, outdata, 4);
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if (--i == 0)
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break;
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RC4_LOOP(indata, outdata, 5);
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if (--i == 0)
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break;
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RC4_LOOP(indata, 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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