134 lines
4.7 KiB
C
134 lines
4.7 KiB
C
/* crypto/rc4/rc4_enc.c */
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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 "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 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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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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#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=(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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