204 lines
6.1 KiB
C
204 lines
6.1 KiB
C
/* crypto/des/enc_read.c */
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/* Copyright (C) 1995-1996 Eric Young (eay@mincom.oz.au)
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* All rights reserved.
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*
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* This file is part of an SSL implementation written
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* by Eric Young (eay@mincom.oz.au).
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* The implementation was written so as to conform with Netscapes SSL
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* specification. This library and applications are
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* FREE FOR COMMERCIAL AND NON-COMMERCIAL USE
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* as long as the following conditions are aheared to.
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*
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* Copyright remains Eric Young's, and as such any Copyright notices in
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* the code are not to be removed. If this code is used in a product,
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* Eric Young should be given attribution as the author of the parts used.
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* This can be in the form of a textual message at program startup or
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* in documentation (online or textual) provided with the package.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Eric Young (eay@mincom.oz.au)
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*
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* The licence and distribution terms for any publically available version or
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* derivative of this code cannot be changed. i.e. this code cannot simply be
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* copied and put under another distribution licence
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* [including the GNU Public Licence.]
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*/
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#include <stdio.h>
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#include <errno.h>
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#include "des_locl.h"
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/* This has some uglies in it but it works - even over sockets. */
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/*extern int errno;*/
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int des_rw_mode=DES_PCBC_MODE;
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int des_enc_read(fd, buf, len, sched, iv)
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int fd;
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char *buf;
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int len;
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des_key_schedule sched;
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des_cblock (*iv);
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{
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/* data to be unencrypted */
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int net_num=0;
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static unsigned char *net=NULL;
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/* extra unencrypted data
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* for when a block of 100 comes in but is des_read one byte at
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* a time. */
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static char *unnet=NULL;
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static int unnet_start=0;
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static int unnet_left=0;
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static char *tmpbuf=NULL;
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int i;
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long num=0,rnum;
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unsigned char *p;
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if (tmpbuf == NULL)
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{
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tmpbuf=(char *)malloc(BSIZE);
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if (tmpbuf == NULL) return(-1);
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}
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if (net == NULL)
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{
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net=(unsigned char *)malloc(BSIZE);
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if (net == NULL) return(-1);
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}
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if (unnet == NULL)
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{
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unnet=(char *)malloc(BSIZE);
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if (unnet == NULL) return(-1);
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}
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/* left over data from last decrypt */
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if (unnet_left != 0)
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{
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if (unnet_left < len)
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{
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/* we still still need more data but will return
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* with the number of bytes we have - should always
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* check the return value */
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memcpy(buf,&(unnet[unnet_start]),
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(unsigned int)unnet_left);
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/* eay 26/08/92 I had the next 2 lines
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* reversed :-( */
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i=unnet_left;
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unnet_start=unnet_left=0;
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}
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else
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{
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memcpy(buf,&(unnet[unnet_start]),(unsigned int)len);
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unnet_start+=len;
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unnet_left-=len;
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i=len;
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}
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return(i);
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}
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/* We need to get more data. */
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if (len > MAXWRITE) len=MAXWRITE;
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/* first - get the length */
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while (net_num < HDRSIZE)
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{
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i=read(fd,&(net[net_num]),(unsigned int)HDRSIZE-net_num);
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if ((i == -1) && (errno == EINTR)) continue;
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if (i <= 0) return(0);
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net_num+=i;
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}
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/* we now have at net_num bytes in net */
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p=net;
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/* num=0; */
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n2l(p,num);
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/* num should be rounded up to the next group of eight
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* we make sure that we have read a multiple of 8 bytes from the net.
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*/
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if ((num > MAXWRITE) || (num < 0)) /* error */
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return(-1);
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rnum=(num < 8)?8:((num+7)/8*8);
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net_num=0;
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while (net_num < rnum)
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{
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i=read(fd,&(net[net_num]),(unsigned int)rnum-net_num);
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if ((i == -1) && (errno == EINTR)) continue;
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if (i <= 0) return(0);
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net_num+=i;
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}
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/* Check if there will be data left over. */
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if (len < num)
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{
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if (des_rw_mode & DES_PCBC_MODE)
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des_pcbc_encrypt((des_cblock *)net,(des_cblock *)unnet,
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num,sched,iv,DES_DECRYPT);
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else
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des_cbc_encrypt((des_cblock *)net,(des_cblock *)unnet,
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num,sched,iv,DES_DECRYPT);
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memcpy(buf,unnet,(unsigned int)len);
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unnet_start=len;
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unnet_left=(int)num-len;
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/* The following line is done because we return num
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* as the number of bytes read. */
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num=len;
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}
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else
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{
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/* >output is a multiple of 8 byes, if len < rnum
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* >we must be careful. The user must be aware that this
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* >routine will write more bytes than he asked for.
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* >The length of the buffer must be correct.
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* FIXED - Should be ok now 18-9-90 - eay */
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if (len < rnum)
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{
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if (des_rw_mode & DES_PCBC_MODE)
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des_pcbc_encrypt((des_cblock *)net,
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(des_cblock *)tmpbuf,
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num,sched,iv,DES_DECRYPT);
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else
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des_cbc_encrypt((des_cblock *)net,
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(des_cblock *)tmpbuf,
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num,sched,iv,DES_DECRYPT);
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/* eay 26/08/92 fix a bug that returned more
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* bytes than you asked for (returned len bytes :-( */
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memcpy(buf,tmpbuf,(unsigned int)num);
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}
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else
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{
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if (des_rw_mode & DES_PCBC_MODE)
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des_pcbc_encrypt((des_cblock *)net,
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(des_cblock *)buf,num,sched,iv,
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DES_DECRYPT);
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else
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des_cbc_encrypt((des_cblock *)net,
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(des_cblock *)buf,num,sched,iv,
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DES_DECRYPT);
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}
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}
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return((int)num);
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}
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