sl@0: /* crypto/des/cfb_enc.c */
sl@0: /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
sl@0:  * All rights reserved.
sl@0:  *
sl@0:  * This package is an SSL implementation written
sl@0:  * by Eric Young (eay@cryptsoft.com).
sl@0:  * The implementation was written so as to conform with Netscapes SSL.
sl@0:  * 
sl@0:  * This library is free for commercial and non-commercial use as long as
sl@0:  * the following conditions are aheared to.  The following conditions
sl@0:  * apply to all code found in this distribution, be it the RC4, RSA,
sl@0:  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
sl@0:  * included with this distribution is covered by the same copyright terms
sl@0:  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
sl@0:  * 
sl@0:  * Copyright remains Eric Young's, and as such any Copyright notices in
sl@0:  * the code are not to be removed.
sl@0:  * If this package is used in a product, Eric Young should be given attribution
sl@0:  * as the author of the parts of the library used.
sl@0:  * This can be in the form of a textual message at program startup or
sl@0:  * in documentation (online or textual) provided with the package.
sl@0:  * 
sl@0:  * Redistribution and use in source and binary forms, with or without
sl@0:  * modification, are permitted provided that the following conditions
sl@0:  * are met:
sl@0:  * 1. Redistributions of source code must retain the copyright
sl@0:  *    notice, this list of conditions and the following disclaimer.
sl@0:  * 2. Redistributions in binary form must reproduce the above copyright
sl@0:  *    notice, this list of conditions and the following disclaimer in the
sl@0:  *    documentation and/or other materials provided with the distribution.
sl@0:  * 3. All advertising materials mentioning features or use of this software
sl@0:  *    must display the following acknowledgement:
sl@0:  *    "This product includes cryptographic software written by
sl@0:  *     Eric Young (eay@cryptsoft.com)"
sl@0:  *    The word 'cryptographic' can be left out if the rouines from the library
sl@0:  *    being used are not cryptographic related :-).
sl@0:  * 4. If you include any Windows specific code (or a derivative thereof) from 
sl@0:  *    the apps directory (application code) you must include an acknowledgement:
sl@0:  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
sl@0:  * 
sl@0:  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
sl@0:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
sl@0:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
sl@0:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
sl@0:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
sl@0:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
sl@0:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
sl@0:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
sl@0:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
sl@0:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
sl@0:  * SUCH DAMAGE.
sl@0:  * 
sl@0:  * The licence and distribution terms for any publically available version or
sl@0:  * derivative of this code cannot be changed.  i.e. this code cannot simply be
sl@0:  * copied and put under another distribution licence
sl@0:  * [including the GNU Public Licence.]
sl@0:  */
sl@0: 
sl@0: #include "e_os.h"
sl@0: #include "des_locl.h"
sl@0: #include <assert.h>
sl@0: 
sl@0: /* The input and output are loaded in multiples of 8 bits.
sl@0:  * What this means is that if you hame numbits=12 and length=2
sl@0:  * the first 12 bits will be retrieved from the first byte and half
sl@0:  * the second.  The second 12 bits will come from the 3rd and half the 4th
sl@0:  * byte.
sl@0:  */
sl@0: /* Until Aug 1 2003 this function did not correctly implement CFB-r, so it
sl@0:  * will not be compatible with any encryption prior to that date. Ben. */
sl@0: EXPORT_C void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits,
sl@0: 		     long length, DES_key_schedule *schedule, DES_cblock *ivec,
sl@0: 		     int enc)
sl@0: 	{
sl@0: 	register DES_LONG d0,d1,v0,v1;
sl@0: 	register unsigned long l=length;
sl@0: 	register int num=numbits/8,n=(numbits+7)/8,i,rem=numbits%8;
sl@0: 	DES_LONG ti[2];
sl@0: 	unsigned char *iv;
sl@0: #ifndef L_ENDIAN
sl@0: 	unsigned char ovec[16];
sl@0: #else
sl@0: 	unsigned int  sh[4];
sl@0: 	unsigned char *ovec=(unsigned char *)sh;
sl@0: 
sl@0: 	/* I kind of count that compiler optimizes away this assertioni,*/
sl@0: 	assert (sizeof(sh[0])==4);	/* as this holds true for all,	*/
sl@0: 					/* but 16-bit platforms...	*/
sl@0: 					
sl@0: #endif
sl@0: 
sl@0: 	if (numbits<=0 || numbits > 64) return;
sl@0: 	iv = &(*ivec)[0];
sl@0: 	c2l(iv,v0);
sl@0: 	c2l(iv,v1);
sl@0: 	if (enc)
sl@0: 		{
sl@0: 		while (l >= (unsigned long)n)
sl@0: 			{
sl@0: 			l-=n;
sl@0: 			ti[0]=v0;
sl@0: 			ti[1]=v1;
sl@0: 			DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT);
sl@0: 			c2ln(in,d0,d1,n);
sl@0: 			in+=n;
sl@0: 			d0^=ti[0];
sl@0: 			d1^=ti[1];
sl@0: 			l2cn(d0,d1,out,n);
sl@0: 			out+=n;
sl@0: 			/* 30-08-94 - eay - changed because l>>32 and
sl@0: 			 * l<<32 are bad under gcc :-( */
sl@0: 			if (numbits == 32)
sl@0: 				{ v0=v1; v1=d0; }
sl@0: 			else if (numbits == 64)
sl@0: 				{ v0=d0; v1=d1; }
sl@0: 			else
sl@0: 				{
sl@0: #ifndef L_ENDIAN
sl@0: 				iv=&ovec[0];
sl@0: 				l2c(v0,iv);
sl@0: 				l2c(v1,iv);
sl@0: 				l2c(d0,iv);
sl@0: 				l2c(d1,iv);
sl@0: #else
sl@0: 				sh[0]=v0, sh[1]=v1, sh[2]=d0, sh[3]=d1;
sl@0: #endif
sl@0: 				if (rem==0)
sl@0: 					memmove(ovec,ovec+num,8);
sl@0: 				else
sl@0: 					for(i=0 ; i < 8 ; ++i)
sl@0: 						ovec[i]=ovec[i+num]<<rem |
sl@0: 							ovec[i+num+1]>>(8-rem);
sl@0: #ifdef L_ENDIAN
sl@0: 				v0=sh[0], v1=sh[1];
sl@0: #else
sl@0: 				iv=&ovec[0];
sl@0: 				c2l(iv,v0);
sl@0: 				c2l(iv,v1);
sl@0: #endif
sl@0: 				}
sl@0: 			}
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		while (l >= (unsigned long)n)
sl@0: 			{
sl@0: 			l-=n;
sl@0: 			ti[0]=v0;
sl@0: 			ti[1]=v1;
sl@0: 			DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT);
sl@0: 			c2ln(in,d0,d1,n);
sl@0: 			in+=n;
sl@0: 			/* 30-08-94 - eay - changed because l>>32 and
sl@0: 			 * l<<32 are bad under gcc :-( */
sl@0: 			if (numbits == 32)
sl@0: 				{ v0=v1; v1=d0; }
sl@0: 			else if (numbits == 64)
sl@0: 				{ v0=d0; v1=d1; }
sl@0: 			else
sl@0: 				{
sl@0: #ifndef L_ENDIAN
sl@0: 				iv=&ovec[0];
sl@0: 				l2c(v0,iv);
sl@0: 				l2c(v1,iv);
sl@0: 				l2c(d0,iv);
sl@0: 				l2c(d1,iv);
sl@0: #else
sl@0: 				sh[0]=v0, sh[1]=v1, sh[2]=d0, sh[3]=d1;
sl@0: #endif
sl@0: 				if (rem==0)
sl@0: 					memmove(ovec,ovec+num,8);
sl@0: 				else
sl@0: 					for(i=0 ; i < 8 ; ++i)
sl@0: 						ovec[i]=ovec[i+num]<<rem |
sl@0: 							ovec[i+num+1]>>(8-rem);
sl@0: #ifdef L_ENDIAN
sl@0: 				v0=sh[0], v1=sh[1];
sl@0: #else
sl@0: 				iv=&ovec[0];
sl@0: 				c2l(iv,v0);
sl@0: 				c2l(iv,v1);
sl@0: #endif
sl@0: 				}
sl@0: 			d0^=ti[0];
sl@0: 			d1^=ti[1];
sl@0: 			l2cn(d0,d1,out,n);
sl@0: 			out+=n;
sl@0: 			}
sl@0: 		}
sl@0: 	iv = &(*ivec)[0];
sl@0: 	l2c(v0,iv);
sl@0: 	l2c(v1,iv);
sl@0: 	v0=v1=d0=d1=ti[0]=ti[1]=0;
sl@0: 	}
sl@0: