/* 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 <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, unsigned long len, const unsigned char *indata,	     unsigned char *outdata)	{        register RC4_INT *d;        register RC4_INT x,y,tx,ty;	int 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...	 *	 * Cavets.	 *	 * - 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 ( ( ((unsigned long)indata  & (sizeof(RC4_CHUNK)-1)) | 	       ((unsigned long)outdata & (sizeof(RC4_CHUNK)-1)) ) == 0 )		{		RC4_CHUNK ichunk,otp;		const union { long one; char little; } is_endian = {1};		/*		 * 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>		 * who also stands for the is_endian union:-)		 *		 * Special notes.		 *		 * - is_endian is declared automatic as doing otherwise		 *   (declaring static) prevents gcc from eliminating		 *   the redundant code;		 * - 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 (!is_endian.little)			{	/* BIG-ENDIAN CASE */# define BESHFT(c)	(((sizeof(RC4_CHUNK)-(c)-1)*8)&(sizeof(RC4_CHUNK)*8-1))			for (;len&-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);				}			if (len)				{				RC4_CHUNK mask=(RC4_CHUNK)-1, ochunk;				ichunk = *(RC4_CHUNK *)indata;				ochunk = *(RC4_CHUNK *)outdata;				otp = 0;				i = BESHFT(0);				mask <<= (sizeof(RC4_CHUNK)-len)<<3;				switch (len&(sizeof(RC4_CHUNK)-1))					{					case 7:	otp  = RC4_STEP<<i, i-=8;					case 6:	otp |= RC4_STEP<<i, i-=8;					case 5:	otp |= RC4_STEP<<i, i-=8;					case 4:	otp |= RC4_STEP<<i, i-=8;					case 3:	otp |= RC4_STEP<<i, i-=8;					case 2:	otp |= RC4_STEP<<i, i-=8;					case 1:	otp |= RC4_STEP<<i, i-=8;					case 0: ; /*						   * it's never the case,						   * but it has to be here						   * for ultrix?						   */					}				ochunk &= ~mask;				ochunk |= (otp^ichunk) & mask;				*(RC4_CHUNK *)outdata = ochunk;				}			key->x=x;     			key->y=y;			return;			}		else			{	/* LITTLE-ENDIAN CASE */# define LESHFT(c)	(((c)*8)&(sizeof(RC4_CHUNK)*8-1))			for (;len&-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);				}			if (len)				{				RC4_CHUNK mask=(RC4_CHUNK)-1, ochunk;				ichunk = *(RC4_CHUNK *)indata;				ochunk = *(RC4_CHUNK *)outdata;				otp = 0;				i   = 0;				mask >>= (sizeof(RC4_CHUNK)-len)<<3;				switch (len&(sizeof(RC4_CHUNK)-1))					{					case 7:	otp  = RC4_STEP,    i+=8;					case 6:	otp |= RC4_STEP<<i, i+=8;					case 5:	otp |= RC4_STEP<<i, i+=8;					case 4:	otp |= RC4_STEP<<i, i+=8;					case 3:	otp |= RC4_STEP<<i, i+=8;					case 2:	otp |= RC4_STEP<<i, i+=8;					case 1:	otp |= RC4_STEP<<i, i+=8;					case 0: ; /*						   * it's never the case,						   * but it has to be here						   * for ultrix?						   */					}				ochunk &= ~mask;				ochunk |= (otp^ichunk) & mask;				*(RC4_CHUNK *)outdata = ochunk;				}			key->x=x;     			key->y=y;			return;			}		}#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=(int)(len>>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;	}