230 lines
7.7 KiB
C
230 lines
7.7 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 <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 RC4(RC4_KEY *key, unsigned long len, 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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#if defined(RC4_CHUNK) && (defined(L_ENDIAN) || defined(B_ENDIAN))
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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 almost 20% on MIPS.
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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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* <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 defined(L_ENDIAN)
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# define SHFT(c) ((c)*8)
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# define MASK(i) (((RC4_CHUNK)-1)>>((sizeof(RC4_CHUNK)-(i))<<3))
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# define SHINC 8
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#elif defined(B_ENDIAN)
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# define SHFT(c) ((sizeof(RC4_CHUNK)-(c)-1)*8)
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# define MASK(i) (((RC4_CHUNK)-1)<<((sizeof(RC4_CHUNK)-(i))<<3))
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# define SHINC -8
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#else
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# error "L_ENDIAN or B_ENDIAN *must* be defined!"
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#endif
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if ( ( ((unsigned long)indata & (sizeof(RC4_CHUNK)-1)) |
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((unsigned long)outdata & (sizeof(RC4_CHUNK)-1)) ) == 0
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) {
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RC4_CHUNK ichunk,cipher;
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for (;len&-sizeof(RC4_CHUNK);len-=sizeof(RC4_CHUNK)) {
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ichunk = *(RC4_CHUNK *)indata;
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cipher = RC4_STEP<<SHFT(0);
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cipher |= RC4_STEP<<SHFT(1);
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cipher |= RC4_STEP<<SHFT(2);
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cipher |= RC4_STEP<<SHFT(3);
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#ifdef RC4_CHUNK_IS_64_BIT
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cipher |= RC4_STEP<<SHFT(4);
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cipher |= RC4_STEP<<SHFT(5);
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cipher |= RC4_STEP<<SHFT(6);
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cipher |= RC4_STEP<<SHFT(7);
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#endif
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*(RC4_CHUNK *)outdata = cipher^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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if (len) {
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RC4_CHUNK mask,ochunk;
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ichunk = *(RC4_CHUNK *)indata;
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ochunk = *(RC4_CHUNK *)outdata;
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cipher = 0;
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i = SHFT(0);
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mask = MASK(len);
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switch (len) {
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#ifdef RC4_CHUNK_IS_64_BIT
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case 7: cipher = RC4_STEP<<SHFT(0), i+=SHINC;
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case 6: cipher |= RC4_STEP<<i, i+=SHINC;
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case 5: cipher |= RC4_STEP<<i, i+=SHINC;
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case 4: cipher |= RC4_STEP<<i, i+=SHINC;
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case 3: cipher |= RC4_STEP<<i, i+=SHINC;
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#else
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case 3: cipher = RC4_STEP<<SHFT(0), i+=SHINC;
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#endif
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case 2: cipher |= RC4_STEP<<i, i+=SHINC;
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case 1: cipher |= RC4_STEP<<i, i+=SHINC;
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case 0: ; /* it's never the case, but it
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has to be here for ultrix? */
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}
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ochunk &= ~mask;
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ochunk |= (cipher^ichunk) & mask;
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*(RC4_CHUNK *)outdata = ochunk;
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}
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}
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else
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#endif
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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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#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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}
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key->x=x;
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key->y=y;
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}
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