text: /* $OpenBSD: cbc_cksm.c,v 1.6 2014/06/12 15:49:28 deraadt 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"
  
  DES_LONG DES_cbc_cksum(const unsigned char *in, DES_cblock *output,
  		       long length, DES_key_schedule *schedule,
  		       const_DES_cblock *ivec)
  	{
  	DES_LONG tout0,tout1,tin0,tin1;
  	long l=length;
  	DES_LONG tin[2];
  	unsigned char *out = &(*output)[0];
  	const unsigned char *iv = &(*ivec)[0];
  
  	c2l(iv,tout0);
  	c2l(iv,tout1);
  	for (; l>0; l-=8)
  		{
  		if (l >= 8)
  			{
  			c2l(in,tin0);
  			c2l(in,tin1);
  			}
  		else
  			c2ln(in,tin0,tin1,l);
  			
  		tin0^=tout0; tin[0]=tin0;
  		tin1^=tout1; tin[1]=tin1;
  		DES_encrypt1((DES_LONG *)tin,schedule,DES_ENCRYPT);
  		/* fix 15/10/91 eay - thanks to keithr@sco.COM */
  		tout0=tin[0];
  		tout1=tin[1];
  		}
  	if (out != NULL)
  		{
  		l2c(tout0,out);
  		l2c(tout1,out);
  		}
  	tout0=tin0=tin1=tin[0]=tin[1]=0;
  	/*
  	  Transform the data in tout1 so that it will
  	  match the return value that the MIT Kerberos
  	  mit_des_cbc_cksum API returns.
  	*/
  	tout1 = ((tout1 >> 24L) & 0x000000FF)
  	      | ((tout1 >> 8L)  & 0x0000FF00)
  	      | ((tout1 << 8L)  & 0x00FF0000)
  	      | ((tout1 << 24L) & 0xFF000000);
  	return(tout1);
  	}
  