/* crypto/rc4/rc4_enc.c */ /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */ #include #include "rc4_locl.h" #include "endian.h" /* RC4 as implemented from a posting from * Newsgroups: sci.crypt * From: sterndark@netcom.com (David Sterndark) * Subject: RC4 Algorithm revealed. * Message-ID: * Date: Wed, 14 Sep 1994 06:35:31 GMT */ /* Note(TL): * RC4 mods to eliminate defines for L_ENDIAN and B_ENDIAN * By: Terrell Larson terr@terralogic.net * Date: Thurs, 30 Sep 1999 */ void RC4(RC4_KEY *key, unsigned long len, unsigned char *indata, unsigned char *outdata) { register RC4_INT *d; register RC4_INT x,y,tx,ty; int i, inc; x=key->x; y=key->y; d=key->data; #if defined(RC4_CHUNK) /* * The original reason for implementing this(*) was the fact that * pre-21164a Alpha CPUs don't have byte load/store instructions * and e.g. a byte store has to be done with 64-bit load, shift, * and, or and finally 64-bit store. Peaking data and operating * at natural word size made it possible to reduce amount of * instructions as well as to perform early read-ahead without * suffering from RAW (read-after-write) hazard. This resulted * in >40%(**) performance improvement (on 21064 box with gcc). * But it's not only Alpha users who win here:-) Thanks to the * early-n-wide read-ahead this implementation also exhibits * >40% speed-up on SPARC and almost 20% on MIPS. * * (*) "this" means code which recognizes the case when input * and output pointers appear to be aligned at natural CPU * word boundary. * (**) i.e. according to 'apps/openssl speed rc4' benchmark, * crypto/rc4/rc4speed.c exhibits almost 70% speed-up. * * */ /* Notes(TL): * * This code should provide at least as fast as a 40% improvement * on MOST cpu's depending on how the cache works. The byte move * code results in a memory access for each byte whereas the CHUNK * code compresses the output side of things to one access per "n" * bytes where "n"=4 for 32 bit machines and "n"=8 for 64 bit * machines. Furthermore - if we are lucky the input data may * load into the cache resulting in much faster fetch speeds. * * We might want to take a close look at the order of operations * defined in RC4_STEP in order to try to take better advantage of * multiple instruction pathways within certain cpu's. I note that * each step of the algorithm for a given byte depends on the prior * step. If we intermingle the operations we might get a significant * performance boost depending on exactly how the compiler sequences * the instructions. I haven't looked at the assembler yet. */ #define RC4_STEP ( \ x=(x+1) &0xff, \ tx=d[x], \ y=(tx+y)&0xff, \ ty=d[y], \ d[y]=tx, \ d[x]=ty, \ (RC4_CHUNK)d[(tx+ty)&0xff] ) #define L_ENDIAN_SHFT(c) ((c)*8) #define L_ENDIAN_MASK(i) (((RC4_CHUNK)-1)>>((sizeof(RC4_CHUNK)-(i))<<3)) #define L_ENDIAN_SHINC 8 #define B_ENDIAN_SHFT(c) ((sizeof(RC4_CHUNK)-(c)-1)*8) #define B_ENDIAN_MASK(i) (((RC4_CHUNK)-1)<<((sizeof(RC4_CHUNK)-(i))<<3)) #define B_ENDIAN_SHINC -8 if ( ( ((unsigned long)indata & (sizeof(RC4_CHUNK)-1)) | ((unsigned long)outdata & (sizeof(RC4_CHUNK)-1)) ) == 0 ) { RC4_CHUNK ichunk,cipher; /* Note(TL): Presumably the compiler is smart enough to * expand the define and resolve it to a constant. * If not, we can use an increment as is used for * the partial word below. * * If we use an increment, then we only need one * for loop - but this should run faster and the * code is only minimally larger. */ if (is_endian.little) { for (;len&-sizeof(RC4_CHUNK);len-=sizeof(RC4_CHUNK)) { ichunk = *(RC4_CHUNK *)indata; cipher = RC4_STEP<>3L); if (i) { for (;;) { RC4_LOOP(indata,outdata,0); RC4_LOOP(indata,outdata,1); RC4_LOOP(indata,outdata,2); RC4_LOOP(indata,outdata,3); RC4_LOOP(indata,outdata,4); RC4_LOOP(indata,outdata,5); RC4_LOOP(indata,outdata,6); RC4_LOOP(indata,outdata,7); #ifdef RC4_INDEX indata+=8; outdata+=8; #endif if (--i == 0) break; } } i=(int)len&0x07; if (i) { for (;;) { RC4_LOOP(indata,outdata,0); if (--i == 0) break; RC4_LOOP(indata,outdata,1); if (--i == 0) break; RC4_LOOP(indata,outdata,2); if (--i == 0) break; RC4_LOOP(indata,outdata,3); if (--i == 0) break; RC4_LOOP(indata,outdata,4); if (--i == 0) break; RC4_LOOP(indata,outdata,5); if (--i == 0) break; RC4_LOOP(indata,outdata,6); if (--i == 0) break; } } } key->x=x; key->y=y; }