/* crypto/rc4/rc4_skey.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"

 #include <openssl/opensslv.h>

 const char RC4_version[]="RC4" OPENSSL_VERSION_PTEXT;

 EXPORT_C const char *RC4_options(void)

 	{

 #ifdef RC4_INDEX

 	if (sizeof(RC4_INT) == 1)

 		return("rc4(idx,char)");

 	else

 		return("rc4(idx,int)");

 #else

 	if (sizeof(RC4_INT) == 1)

 		return("rc4(ptr,char)");

 	else

 		return("rc4(ptr,int)");

 #endif

 	}

 /* 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

  */

 EXPORT_C void RC4_set_key(RC4_KEY *key, int len, const unsigned char *data)

 	{

         register RC4_INT tmp;

         register int id1,id2;

         register RC4_INT *d;

         unsigned int i;

         d= &(key->data[0]);

         key->x = 0;     

         key->y = 0;     

         id1=id2=0;     

 #define SK_LOOP(d,n) { \

 		tmp=d[(n)]; \

 		id2 = (data[id1] + tmp + id2) & 0xff; \

 		if (++id1 == len) id1=0; \

 		d[(n)]=d[id2]; \

 		d[id2]=tmp; }

 #if defined(OPENSSL_CPUID_OBJ) && !defined(OPENSSL_NO_ASM)

 # if	defined(__i386)   || defined(__i386__)   || defined(_M_IX86) || \

 	defined(__INTEL__) || \

 	defined(__x86_64) || defined(__x86_64__) || defined(_M_AMD64)

 	if (sizeof(RC4_INT) > 1) {

 		/*

 		 * Unlike all other x86 [and x86_64] implementations,

 		 * Intel P4 core [including EM64T] was found to perform

 		 * poorly with wider RC4_INT. Performance improvement

 		 * for IA-32 hand-coded assembler turned out to be 2.8x

 		 * if re-coded for RC4_CHAR! It's however inappropriate

 		 * to just switch to RC4_CHAR for x86[_64], as non-P4

 		 * implementations suffer from significant performance

 		 * losses then, e.g. PIII exhibits >2x deterioration,

 		 * and so does Opteron. In order to assure optimal

 		 * all-round performance, let us [try to] detect P4 at

 		 * run-time by checking upon HTT bit in CPU capability

 		 * vector and set up compressed key schedule, which is

 		 * recognized by correspondingly updated assembler

 		 * module...

 		 *				<appro@fy.chalmers.se>

 		 */

 		if (OPENSSL_ia32cap_P & (1<<28)) {

 			unsigned char *cp=(unsigned char *)d;

 			for (i=0;i<256;i++) cp[i]=i;

 			for (i=0;i<256;i++) SK_LOOP(cp,i);

 			/* mark schedule as compressed! */

 			d[256/sizeof(RC4_INT)]=-1;

 			return;

 		}

 	}

 # endif

 #endif

 	for (i=0; i < 256; i++) d[i]=i;

 	for (i=0; i < 256; i+=4)

 		{

 		SK_LOOP(d,i+0);

 		SK_LOOP(d,i+1);

 		SK_LOOP(d,i+2);

 		SK_LOOP(d,i+3);

 		}

 	}