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/*********************************************************************/
/*-文件名：des.c */
/*- */
/*-功能： 实现DES加密算法的加密解密功能 */
/*- */
/*-说明：des算法的实现代码 */
/*- 能够实现56位或56*n密钥的des算法，可以通过该程序提供的接口 */
/*- 进行数据的加密，保证数据在传送过程的安全性 */
/*- */
/*- */
/*-该程序的所有权利由作者保留 */
/*- */
/*- */
/*-版本号：1.0.0(2002.4) */
/*- */
/*- */
/*-AUTHOR:吴真(WUZHEN) */
/*- */
/*********************************************************************/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <memory.h>
#include <malloc.h>
#include "des.h"

#define SUCCESS 0
#define FAIL -1

#define READFILESIZE 512

#define WZ_COMMEND_NUM 4
#define WZUSEHELPNUM 19
#define DESONE 1
#define DESTHREE 2
#define DESMULTI 3
INT8 *WZ_Commend_Help[] =
{

"基于DES的加密解密工具v1.0 ",/*0*/
"追求卓越,勇于创新 ",
"----著者 : 吴真--- ",
" "
};

INT8 *WZ_USE_HELP[]={
"输入5+n个参数:",
"\t1.可执行文件名 *.exe",
"\t2.操作类型 1:一层加密;2:一层解密;",
"\t\t13:N层单密钥加密;23:N层单密钥解密;",
"\t\t39:N层多密钥加密;49:N层多密钥解密",
"\t3.读出数据的文件名*.txt",
"\t4.写入数据的文件名*.txt",
"\t5.密钥(8字节例如:wuzhen12)",
"\t[6].N层单密钥的层数或者...二层加密│解密密钥",
"\t[7].三层加密│解密密钥",
"\t[8]. ...",
"\t[N].N层加密│解密密钥",
"\t 例1: des 1 1.txt 2.txt 12345678",
"\t : des 2 2.txt 3.txt 12345678",
"\t 例2: des 13 1.txt 2.txt tiantian 5",
"\t : des 23 2.txt 3.txt tiantian 5",
"\t 例3: des 39 1.txt 2.txt 12345678 tiantian gaoxinma",
"\t : des 49 2.txt 3.txt 12345678 tiantian gaoxinma",
"******************************"
};

INT32 hextofile( ULONG8 *buf ,FILE *writefile, ULONG32 length);/*以16进制写入文件*/
INT32 encodehex(ULONG8 *tobuf,ULONG8 *frombuf,ULONG32 len);/*16进制解码*/

INT32 file_enc(FILE *readfile,FILE *writefile,
ULONG8 *key,ULONG32 keynum,
ULONG8 **superkey,ULONG32 n_superkey,
ULONG8 flag);
INT32 file_dec(FILE *readfile,FILE *writefile,
ULONG8 *key,ULONG32 keynum,
ULONG8 **superkey,ULONG32 n_superkey,
ULONG8 flag);
void wz_print_help();

INT32 main(INT32 argc,INT8 *argv[])
{
INT8 *FILENAME1,*FILENAME2;
FILE *fp, *fp2;
ULONG8 *key ;
ULONG8 **superkey ;/*n层加密解密密钥*/
ULONG8 n_superkey ;
ULONG32 num;

if ( argc >= 5 && (atoi(argv[1]) == 39 ││ atoi(argv[1]) == 49 ) )
{
n_superkey = argc - 4 ;
superkey = ( INT8 **)calloc(1, n_superkey*sizeof( void *) ) ;
for ( num = 0 ; num < n_superkey ; num++)
{
superkey[num] = argv[4+num] ;
}

}
else if ( argc == 6 && (atoi(argv[1]) == 13 ││ atoi(argv[1]) == 23 ) && (atoi(argv[5])) > 0)
{

}
else if ( argc == 5 && ( atoi(argv[1]) == 1 ││ atoi(argv[1]) == 2 ))
{

}
else
{
wz_print_help();
return FAIL;
}
FILENAME1 = argv[2];
FILENAME2 = argv[3];
if ((fp= fopen(FILENAME1,"rb")) == NULL ││ (fp2 = fopen(FILENAME2,"wb"))==NULL)
{

printf("Can't open file\n");
return FAIL;
}

key = argv[4] ;
switch( atoi(argv[1] ))
{
case 1: /*加密*/
file_enc(fp,fp2,key,0, NULL,0, DESONE);
printf("\n \tDES 一层加密完毕,密文存于%s文件\n",FILENAME2);
break;
case 2:
file_dec(fp,fp2,key,0, NULL, 0,DESONE);
printf("\n \tDES 一层解密完毕,密文存于%s文件\n",FILENAME2);
break;
case 13:
file_enc(fp,fp2,key,atoi(argv[5]),NULL,0,DESTHREE);
printf("\n \tDES %u层单密钥加密完毕,密文存于%s文件\n",atoi(argv[5]),FILENAME2);
break;
case 23:
file_dec(fp,fp2,key,atoi(argv[5]),NULL,0,DESTHREE);
printf("\n \tDES %u层单密钥解密完毕,密文存于%s文件\n",atoi(argv[5]),FILENAME2);
break;
case 39:
file_enc(fp,fp2,NULL,0,superkey,n_superkey,DESMULTI);
printf("\n \tDES 多密钥加密完毕,密文存于%s文件\n",FILENAME2);
free(superkey);
superkey = NULL;
break;
case 49:
file_dec(fp,fp2,NULL,0,superkey,n_superkey,DESMULTI);
printf("\n \tDES 多密钥加密完毕,密文存于%s文件\n",FILENAME2);
free(superkey);
superkey = NULL;
break;
default:
printf("请选择是加密│解密 plese choose encrypt│deencrypt\n");
break;
}

fclose(fp);
fclose(fp2);
return SUCCESS;

}

void wz_print_help()
{
INT32 i ;
printf("\t");
for ( i = 0 ; i < 22 ; i++)
{
printf("%c ",5);
}
printf("\n");
for( i = 0 ; i < WZ_COMMEND_NUM ; i++)
{
printf("\t%c\t%s %c\n",5,WZ_Commend_Help[i],5);
}
printf("\t");
for ( i = 0 ; i < 22 ; i++)
{
printf("%c ",5);
}
printf("\n");
for( i = 0 ; i < WZUSEHELPNUM ; i++)
{
printf("\t%s\n",WZ_USE_HELP[i]);
}
return ;
}

INT32 file_enc(FILE *readfile,FILE *writefile,
ULONG8 *key,ULONG32 keynum,
ULONG8 **superkey,ULONG32 n_superkey,
ULONG8 flag)
{
INT32 filelen = 0,readlen = 0,writelen = 0;
ULONG32 totalfilelen = 0 ;/*统计实际的文件的长度*/
ULONG8 readbuf[READFILESIZE] = { 0 };
filelen = fread( readbuf, sizeof( INT8 ), READFILESIZE, readfile );
while( filelen == READFILESIZE )
{
totalfilelen += READFILESIZE;
switch(flag)
{
case DESONE:
des( readbuf,key,READFILESIZE);
break;
case DESTHREE:
des3( readbuf, key ,keynum,READFILESIZE);
break;
case DESMULTI:
desN( readbuf, superkey ,n_superkey,READFILESIZE);
break;
}
hextofile( readbuf, writefile, READFILESIZE );/*以16进制形式写入文件*/
memset(readbuf,0,READFILESIZE);
filelen = fread( readbuf, sizeof( INT8 ), READFILESIZE, readfile );
}
/*这是从文件中读出的最后一批数据,长度可能会等于0,所以要先判断*/

if ( filelen > 0 )
{
/*如果从文件中读出的长度不等于0,那么肯定有8个字节以上的空间
文件长度存在最后8个字节中*/
totalfilelen += filelen;
memcpy( &readbuf[READFILESIZE-8], (ULONG8*)&totalfilelen,4);
switch(flag)
{
case DESONE:
des( readbuf,key,READFILESIZE);
break;
case DESTHREE:
des3( readbuf, key ,keynum,READFILESIZE);
break;
case DESMULTI:
desN( readbuf, superkey ,n_superkey,READFILESIZE);
break;
}
hextofile( readbuf, writefile,READFILESIZE );/*以16进制形式写入文件*/
memset(readbuf,0 ,READFILESIZE);
}
else /*filelen == 0*/
{
memcpy( &readbuf[0], (ULONG8*)&totalfilelen,4);
switch(flag)
{
case DESONE:
des( readbuf,key,8);
break;
case DESTHREE:
des3( readbuf, key ,keynum,8);
break;
case DESMULTI:
desN( readbuf, superkey ,n_superkey,8);
break;
}
hextofile( readbuf, writefile, 8);/*以16进制形式写入文件*/
}
return SUCCESS;
}

INT32 file_dec(FILE *readfile,FILE *writefile,
ULONG8 *key,ULONG32 keynum,
ULONG8 **superkey,ULONG32 n_superkey,
ULONG8 flag)
{
INT32 filelen = 0,readlen = 0,writelen = 0;
ULONG32 totalfilelen = 0 ;/*统计实际的文件的长度*/
INT32 num = 0;
ULONG8 readbuf[READFILESIZE] = { 0 };
ULONG8 sendbuf[READFILESIZE*2] = { 0 };

fseek(readfile,-16,SEEK_END);/*最后16个字节的表示文件长度的空间*/
filelen = fread( sendbuf, sizeof( INT8 ), 16, readfile );
encodehex( readbuf,sendbuf,8);
switch(flag)
{
case DESONE:
Ddes( readbuf,key,8);
break;
case DESTHREE:
Ddes3( readbuf, key ,keynum,8);
break;
case DESMULTI:
DdesN( readbuf, superkey ,n_superkey,8);
break;
}
/*解密*/
memcpy((ULONG8*)&totalfilelen, &readbuf[0],4);/*得到文件总长*/
memset(readbuf,0 ,8);
memset(sendbuf,0 ,16);

num = totalfilelen/READFILESIZE;/*有几个READFILESIZE组*/
totalfilelen %= READFILESIZE;

fseek(readfile,0,SEEK_SET);/*跳到文件头*/
while(num--)
{
filelen = fread( sendbuf, sizeof( INT8 ), READFILESIZE*2, readfile );
encodehex( readbuf,sendbuf,READFILESIZE);
switch(flag)
{
case DESONE:
Ddes( readbuf,key,READFILESIZE);
break;
case DESTHREE:
Ddes3( readbuf, key ,keynum,READFILESIZE);
break;
case DESMULTI:
DdesN( readbuf, superkey ,n_superkey,READFILESIZE);
break;
}

writelen = fwrite(readbuf, sizeof( INT8 ), READFILESIZE, writefile);
memset(readbuf,0 ,READFILESIZE);
memset(sendbuf,0 ,READFILESIZE*2);
}
if ( totalfilelen > 0 )/*最后一块有多余的元素*/
{
filelen = fread( sendbuf, sizeof( INT8 ), READFILESIZE*2, readfile );
encodehex( readbuf,sendbuf,READFILESIZE);
switch(flag)
{
case DESONE:
Ddes( readbuf,key,READFILESIZE);
break;
case DESTHREE:
Ddes3( readbuf, key ,keynum,READFILESIZE);
break;
case DESMULTI:
DdesN( readbuf, superkey ,n_superkey,READFILESIZE);
break;
}
writelen = fwrite(readbuf, sizeof( INT8 ), totalfilelen, writefile);
memset(readbuf,0 ,READFILESIZE);
memset(sendbuf,0 ,READFILESIZE*2);

}
return SUCCESS;
}

INT32 hextofile( ULONG8 *buf ,FILE *writefile, ULONG32 length)
{
ULONG32 writelen = 0 ;
/*以16进制形式写入文件*/
while( writelen < length)
{
if(buf[writelen] == 0)
{
fprintf( writefile, "%x", 0 );
fprintf( writefile, "%x", 0 );
}
else if (buf[writelen] < 0x10)
{
fprintf( writefile, "%x", 0 );
fprintf( writefile, "%x", buf[writelen] );
}
else
{
fprintf( writefile, "%x", buf[writelen] );

}
writelen++;

}
return SUCCESS;
}
INT32 encodehex(ULONG8 *tobuf,ULONG8 *frombuf,ULONG32 len)
{
ULONG8 *readfirst = frombuf ;
ULONG8 *readend = &frombuf[1] ;
INT8 *s;
ULONG8 y[2] ;
ULONG32 i;
for ( i = 0 ; i < len ; i++)
{
y[0] = *readfirst ;
y[1] = *readend ;
readfirst += 2 ;
readend += 2 ;
tobuf[i] = (ULONG8)strtol((INT8*)y, &s, 16);
}
return SUCCESS;
}