/* $OpenBSD: rc4_enc.c,v 1.17 2021/11/09 18:40:21 bcook Exp $ */ /* 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 <endian.h> #include <openssl/rc4.h> #include "rc4_locl.h" /* RC4 as implemented from a posting from * Newsgroups: sci.crypt * From: sterndark@netcom.com (David Sterndark) * Subject: RC4 Algorithm revealed. * Message-ID: <sternCvKL4B.Hyy@netcom.com> * Date: Wed, 14 Sep 1994 06:35:31 GMT */ void RC4(RC4_KEY *key, size_t len, const unsigned char *indata, unsigned char *outdata) { RC4_INT *d; RC4_INT x, y,tx, ty; size_t i; 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 20-30% on 64-bit MIPS (depending * on sizeof(RC4_INT)). * * (*) "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... * * Caveats. * * - RC4_CHUNK="unsigned long long" should be a #1 choice for * UltraSPARC. Unfortunately gcc generates very slow code * (2.5-3 times slower than one generated by Sun's WorkShop * C) and therefore gcc (at least 2.95 and earlier) should * always be told that RC4_CHUNK="unsigned long". * * <appro@fy.chalmers.se> */ # 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]\ ) if ((((size_t)indata & (sizeof(RC4_CHUNK) - 1)) | ((size_t)outdata & (sizeof(RC4_CHUNK) - 1))) == 0 ) { RC4_CHUNK ichunk, otp; /* * I reckon we can afford to implement both endian * cases and to decide which way to take at run-time * because the machine code appears to be very compact * and redundant 1-2KB is perfectly tolerable (i.e. * in case the compiler fails to eliminate it:-). By * suggestion from Terrel Larson <terr@terralogic.net>. * * Special notes. * * - compilers (those I've tried) don't seem to have * problems eliminating either the operators guarded * by "if (sizeof(RC4_CHUNK)==8)" or the condition * expressions themselves so I've got 'em to replace * corresponding #ifdefs from the previous version; * - I chose to let the redundant switch cases when * sizeof(RC4_CHUNK)!=8 be (were also #ifdefed * before); * - in case you wonder "&(sizeof(RC4_CHUNK)*8-1)" in * [LB]ESHFT guards against "shift is out of range" * warnings when sizeof(RC4_CHUNK)!=8 * * <appro@fy.chalmers.se> */ #if BYTE_ORDER == BIG_ENDIAN # define BESHFT(c) (((sizeof(RC4_CHUNK)-(c)-1)*8)&(sizeof(RC4_CHUNK)*8-1)) for (; len & (0 - sizeof(RC4_CHUNK)); len -= sizeof(RC4_CHUNK)) { ichunk = *(RC4_CHUNK *)indata; otp = RC4_STEP << BESHFT(0); otp |= RC4_STEP << BESHFT(1); otp |= RC4_STEP << BESHFT(2); otp |= RC4_STEP << BESHFT(3); if (sizeof(RC4_CHUNK) == 8) { otp |= RC4_STEP << BESHFT(4); otp |= RC4_STEP << BESHFT(5); otp |= RC4_STEP << BESHFT(6); otp |= RC4_STEP << BESHFT(7); } *(RC4_CHUNK *)outdata = otp^ichunk; indata += sizeof(RC4_CHUNK); outdata += sizeof(RC4_CHUNK); } #else # define LESHFT(c) (((c)*8)&(sizeof(RC4_CHUNK)*8-1)) for (; len & (0 - sizeof(RC4_CHUNK)); len -= sizeof(RC4_CHUNK)) { ichunk = *(RC4_CHUNK *)indata; otp = RC4_STEP; otp |= RC4_STEP << 8; otp |= RC4_STEP << 16; otp |= RC4_STEP << 24; if (sizeof(RC4_CHUNK) == 8) { otp |= RC4_STEP << LESHFT(4); otp |= RC4_STEP << LESHFT(5); otp |= RC4_STEP << LESHFT(6); otp |= RC4_STEP << LESHFT(7); } *(RC4_CHUNK *)outdata = otp ^ ichunk; indata += sizeof(RC4_CHUNK); outdata += sizeof(RC4_CHUNK); } #endif } #endif #define LOOP(in,out) \ x=((x+1)&0xff); \ tx=d[x]; \ y=(tx+y)&0xff; \ d[x]=ty=d[y]; \ d[y]=tx; \ (out) = d[(tx+ty)&0xff]^ (in); #ifndef RC4_INDEX #define RC4_LOOP(a,b,i) LOOP(*((a)++),*((b)++)) #else #define RC4_LOOP(a,b,i) LOOP(a[i],b[i]) #endif i = len >> 3; 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 = 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; }
