/* 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);

		}

	}