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      1 /* crypto/des/ofb64enc.c */
      2 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com)
      3  * All rights reserved.
      4  *
      5  * This package is an SSL implementation written
      6  * by Eric Young (eay (at) cryptsoft.com).
      7  * The implementation was written so as to conform with Netscapes SSL.
      8  *
      9  * This library is free for commercial and non-commercial use as long as
     10  * the following conditions are aheared to.  The following conditions
     11  * apply to all code found in this distribution, be it the RC4, RSA,
     12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
     13  * included with this distribution is covered by the same copyright terms
     14  * except that the holder is Tim Hudson (tjh (at) cryptsoft.com).
     15  *
     16  * Copyright remains Eric Young's, and as such any Copyright notices in
     17  * the code are not to be removed.
     18  * If this package is used in a product, Eric Young should be given attribution
     19  * as the author of the parts of the library used.
     20  * This can be in the form of a textual message at program startup or
     21  * in documentation (online or textual) provided with the package.
     22  *
     23  * Redistribution and use in source and binary forms, with or without
     24  * modification, are permitted provided that the following conditions
     25  * are met:
     26  * 1. Redistributions of source code must retain the copyright
     27  *    notice, this list of conditions and the following disclaimer.
     28  * 2. Redistributions in binary form must reproduce the above copyright
     29  *    notice, this list of conditions and the following disclaimer in the
     30  *    documentation and/or other materials provided with the distribution.
     31  * 3. All advertising materials mentioning features or use of this software
     32  *    must display the following acknowledgement:
     33  *    "This product includes cryptographic software written by
     34  *     Eric Young (eay (at) cryptsoft.com)"
     35  *    The word 'cryptographic' can be left out if the rouines from the library
     36  *    being used are not cryptographic related :-).
     37  * 4. If you include any Windows specific code (or a derivative thereof) from
     38  *    the apps directory (application code) you must include an acknowledgement:
     39  *    "This product includes software written by Tim Hudson (tjh (at) cryptsoft.com)"
     40  *
     41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
     42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     51  * SUCH DAMAGE.
     52  *
     53  * The licence and distribution terms for any publically available version or
     54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
     55  * copied and put under another distribution licence
     56  * [including the GNU Public Licence.]
     57  */
     58 
     59 #include "des_locl.h"
     60 
     61 /* The input and output encrypted as though 64bit ofb mode is being
     62  * used.  The extra state information to record how much of the
     63  * 64bit block we have used is contained in *num;
     64  */
     65 void DES_ofb64_encrypt(register const unsigned char *in,
     66 		       register unsigned char *out, long length,
     67 		       DES_key_schedule *schedule, DES_cblock *ivec, int *num)
     68 	{
     69 	register DES_LONG v0,v1,t;
     70 	register int n= *num;
     71 	register long l=length;
     72 	DES_cblock d;
     73 	register unsigned char *dp;
     74 	DES_LONG ti[2];
     75 	unsigned char *iv;
     76 	int save=0;
     77 
     78 	iv = &(*ivec)[0];
     79 	c2l(iv,v0);
     80 	c2l(iv,v1);
     81 	ti[0]=v0;
     82 	ti[1]=v1;
     83 	dp=d;
     84 	l2c(v0,dp);
     85 	l2c(v1,dp);
     86 	while (l--)
     87 		{
     88 		if (n == 0)
     89 			{
     90 			DES_encrypt1(ti,schedule,DES_ENCRYPT);
     91 			dp=d;
     92 			t=ti[0]; l2c(t,dp);
     93 			t=ti[1]; l2c(t,dp);
     94 			save++;
     95 			}
     96 		*(out++)= *(in++)^d[n];
     97 		n=(n+1)&0x07;
     98 		}
     99 	if (save)
    100 		{
    101 		v0=ti[0];
    102 		v1=ti[1];
    103 		iv = &(*ivec)[0];
    104 		l2c(v0,iv);
    105 		l2c(v1,iv);
    106 		}
    107 	t=v0=v1=ti[0]=ti[1]=0;
    108 	*num=n;
    109 	}
    110 
    111