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/* crypto/rc4/rc4_enc.org */ |
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/* Copyright (C) 1995-1997 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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|
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#include "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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|
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void RC4(key, len, indata, outdata) |
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RC4_KEY *key; |
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unsigned long len; |
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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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int i; |
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|
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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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|
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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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|
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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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|
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i= -(int)len; |
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i=(int)(len>>3L); |
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if (i) |
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{ |
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for (;;) |
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{ |
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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) break; |
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} |
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} |
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i=(int)len&0x07; |
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if (i) |
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{ |
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for (;;) |
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{ |
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RC4_LOOP(indata,outdata,0); if (--i == 0) break; |
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RC4_LOOP(indata,outdata,1); if (--i == 0) break; |
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RC4_LOOP(indata,outdata,2); if (--i == 0) break; |
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RC4_LOOP(indata,outdata,3); if (--i == 0) break; |
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RC4_LOOP(indata,outdata,4); if (--i == 0) break; |
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RC4_LOOP(indata,outdata,5); if (--i == 0) break; |
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RC4_LOOP(indata,outdata,6); if (--i == 0) 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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