text: /* $OpenBSD: cfb64ede.c,v 1.9 2015/02/07 13:19:15 doug 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 "des_locl.h"
  
  /* The input and output encrypted as though 64bit cfb mode is being
   * used.  The extra state information to record how much of the
   * 64bit block we have used is contained in *num;
   */
  
  void DES_ede3_cfb64_encrypt(const unsigned char *in, unsigned char *out,
  			    long length, DES_key_schedule *ks1,
  			    DES_key_schedule *ks2, DES_key_schedule *ks3,
  			    DES_cblock *ivec, int *num, int enc)
  	{
  	DES_LONG v0,v1;
  	long l=length;
  	int n= *num;
  	DES_LONG ti[2];
  	unsigned char *iv,c,cc;
  
  	iv=&(*ivec)[0];
  	if (enc)
  		{
  		while (l--)
  			{
  			if (n == 0)
  				{
  				c2l(iv,v0);
  				c2l(iv,v1);
  
  				ti[0]=v0;
  				ti[1]=v1;
  				DES_encrypt3(ti,ks1,ks2,ks3);
  				v0=ti[0];
  				v1=ti[1];
  
  				iv = &(*ivec)[0];
  				l2c(v0,iv);
  				l2c(v1,iv);
  				iv = &(*ivec)[0];
  				}
  			c= *(in++)^iv[n];
  			*(out++)=c;
  			iv[n]=c;
  			n=(n+1)&0x07;
  			}
  		}
  	else
  		{
  		while (l--)
  			{
  			if (n == 0)
  				{
  				c2l(iv,v0);
  				c2l(iv,v1);
  
  				ti[0]=v0;
  				ti[1]=v1;
  				DES_encrypt3(ti,ks1,ks2,ks3);
  				v0=ti[0];
  				v1=ti[1];
  
  				iv = &(*ivec)[0];
  				l2c(v0,iv);
  				l2c(v1,iv);
  				iv = &(*ivec)[0];
  				}
  			cc= *(in++);
  			c=iv[n];
  			iv[n]=cc;
  			*(out++)=c^cc;
  			n=(n+1)&0x07;
  			}
  		}
  	v0=v1=ti[0]=ti[1]=c=cc=0;
  	*num=n;
  	}
  
  /* This is compatible with the single key CFB-r for DES, even thought that's
   * not what EVP needs.
   */
  
  void DES_ede3_cfb_encrypt(const unsigned char *in,unsigned char *out,
  			  int numbits,long length,DES_key_schedule *ks1,
  			  DES_key_schedule *ks2,DES_key_schedule *ks3,
  			  DES_cblock *ivec,int enc)
  	{
  	DES_LONG d0,d1,v0,v1;
  	unsigned long l=length,n=((unsigned int)numbits+7)/8;
  	int num=numbits,i;
  	DES_LONG ti[2];
  	unsigned char *iv;
  	unsigned char ovec[16];
  
  	if (num > 64) return;
  	iv = &(*ivec)[0];
  	c2l(iv,v0);
  	c2l(iv,v1);
  	if (enc)
  		{
  		while (l >= n)
  			{
  			l-=n;
  			ti[0]=v0;
  			ti[1]=v1;
  			DES_encrypt3(ti,ks1,ks2,ks3);
  			c2ln(in,d0,d1,n);
  			in+=n;
  			d0^=ti[0];
  			d1^=ti[1];
  			l2cn(d0,d1,out,n);
  			out+=n;
  			/* 30-08-94 - eay - changed because l>>32 and
  			 * l<<32 are bad under gcc :-( */
  			if (num == 32)
  				{ v0=v1; v1=d0; }
  			else if (num == 64)
  				{ v0=d0; v1=d1; }
  			else
  				{
  				iv=&ovec[0];
  				l2c(v0,iv);
  				l2c(v1,iv);
  				l2c(d0,iv);
  				l2c(d1,iv);
  				/* shift ovec left most of the bits... */
  				memmove(ovec,ovec+num/8,8+(num%8 ? 1 : 0));
  				/* now the remaining bits */
  				if(num%8 != 0)
  					for(i=0 ; i < 8 ; ++i)
  						{
  						ovec[i]<<=num%8;
  						ovec[i]|=ovec[i+1]>>(8-num%8);
  						}
  				iv=&ovec[0];
  				c2l(iv,v0);
  				c2l(iv,v1);
  				}
  			}
  		}
  	else
  		{
  		while (l >= n)
  			{
  			l-=n;
  			ti[0]=v0;
  			ti[1]=v1;
  			DES_encrypt3(ti,ks1,ks2,ks3);
  			c2ln(in,d0,d1,n);
  			in+=n;
  			/* 30-08-94 - eay - changed because l>>32 and
  			 * l<<32 are bad under gcc :-( */
  			if (num == 32)
  				{ v0=v1; v1=d0; }
  			else if (num == 64)
  				{ v0=d0; v1=d1; }
  			else
  				{
  				iv=&ovec[0];
  				l2c(v0,iv);
  				l2c(v1,iv);
  				l2c(d0,iv);
  				l2c(d1,iv);
  				/* shift ovec left most of the bits... */
  				memmove(ovec,ovec+num/8,8+(num%8 ? 1 : 0));
  				/* now the remaining bits */
  				if(num%8 != 0)
  					for(i=0 ; i < 8 ; ++i)
  						{
  						ovec[i]<<=num%8;
  						ovec[i]|=ovec[i+1]>>(8-num%8);
  						}
  				iv=&ovec[0];
  				c2l(iv,v0);
  				c2l(iv,v1);
  				}
  			d0^=ti[0];
  			d1^=ti[1];
  			l2cn(d0,d1,out,n);
  			out+=n;
  			}
  		}
  	iv = &(*ivec)[0];
  	l2c(v0,iv);
  	l2c(v1,iv);
  	v0=v1=d0=d1=ti[0]=ti[1]=0;
  	}
  
  