#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#define ENCRYPT 0 /* DES 方向 */
#define DECRYPT 1
static unsigned char key[10];
static int pc_1_c[28]=
{
57,49,41,33,25,17,9
,1,58,50,42,34,26,18
,10,2,59,51,43,35,27
,19,11,3,60,52,44,36
};
static int pc_1_d[28]=
{
63,55,47,39,31,23,15
,7,62,54,46,38,30,22
,14,6,61,53,45,37,29
,21,13,5,28,20,12,4
};
static int pc_2[48]=
{
14,17,11,24,1,5,
3,28,15,6,21,10,
23,19,12,4,26,8,
16,7,27,20,13,2,
41,52,31,37,47,55,
30,40,51,45,33,48,
44,49,39,56,34,53,
46,42,50,36,29,32
};
static int ls_count[16]=
{
1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1
};
static int ip_tab[64]=
{
58,50,42,34,26,18,10,2,
60,52,44,36,28,20,12,4,
62,54,46,38,30,22,14,6,
64,56,48,40,32,24,16,8,
57,49,41,33,25,17,9,1,
59,51,43,35,27,19,11,3,
61,53,45,37,29,21,13,5,
63,55,47,39,31,23,15,7
};
static int _ip_tab[64]=
{
40,8,48,16,56,24,64,32,
39,7,47,15,55,23,63,31,
38,6,46,14,54,22,62,30,
37,5,45,13,53,21,61,29,
36,4,44,12,52,20,60,28,
35,3,43,11,51,19,59,27,
34,2,42,10,50,18,58,26,
33,1,41,9,49,17,57,25
};
static int e_r[48]=
{
32,1,2,3,4,5,4,5,6,7,8,9,
8,9,10,11,12,13,12,13,14,15,16,17,
16,17,18,19,20,21,20,21,22,23,24,25,
24,25,26,27,28,29,28,29,30,31,32,1
};
static int P[32]=
{
16,7,20,21,29,12,28,17,
1,15,23,26,5,18,31,10,
2,8,24,14,32,27,3,9,
19,13,30,6,22,11,4,25
};
static int SSS[17][4][16]=
{
{
{14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7},
{0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8},/* err on */
{4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0},
{15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13}
},
{
{15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10},
{3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5},
{0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15},
{13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9}
},
{
{10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8},
{13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1},
{13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7},
{1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12}
},
{
{7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15},
{13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9},
{10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4},
{3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14}
}, /* err on */
{
{2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9},
{14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6}, /* err on */
{4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14},
{11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3}
},
{
{12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11},
{10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8},
{9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6},
{4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13}
},
{
{4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1},
{13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6},
{1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2},
{6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12}
},
{
{13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7},
{1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2},
{7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8},
{2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11}
}
};
static unsigned char C[17][28],D[17][28],K[17][48];
void DES(unsigned char *source,unsigned char *dest,unsigned char *key,unsigned char flag);
static void expand0(unsigned char *in,char *out);
static void setkeystar(unsigned char bits[64]);
static void encrypt0(unsigned char *text,unsigned char *mtext);
static void discrypt0(unsigned char *mtext,unsigned char *text);
static void compress0(char *out,unsigned char *in);
static void LS(char *bits,char *buffer,int count);
static void son(char *cc,char *dd,char *kk);
static void ip(unsigned char *text,char *ll,char *rr);
static void _ip(unsigned char *text,char *ll,char *rr);
static void F(int n,char *ll,char *rr,char *LL,char *RR);
static void s_box(char *aa,char *bb);
int RandomReadEnc(char *input, int position, int len, char *filename);
int RandomWriteEnc(char *input, int position, int len, char *filename);
void DES(unsigned char *source,unsigned char *dest,unsigned char *key,unsigned char flag)
{
unsigned char tmp[64];
expand0(key, (char *)tmp);
setkeystar(tmp);
if( flag == ENCRYPT)
encrypt0(source, dest);
else if (flag == DECRYPT)
discrypt0(source, dest);
else {
printf("flag is invalidated");
exit(0);
}
}
void Do_XOR(unsigned char *dest,unsigned char *source,int size)
{
int i;
for(i=0; i<size; i++)
dest[i] ^= source[i];
}
static void encrypt0(unsigned char *text,unsigned char *mtext)
{
char ll[64],rr[64],LL[64],RR[64];
char tmp[64];
int i,j;
ip(text,ll,rr);
for (i=1; i<17; i++)
{
F(i,ll,rr,LL,RR);
for (j=0; j<32; j++)
{
ll[j]=LL[j];
rr[j]=RR[j];
}
}
_ip((unsigned char *)tmp,rr,ll);
compress0(tmp,mtext);
}
static void discrypt0(unsigned char *mtext,unsigned char *text)
{
char ll[64],rr[64],LL[64],RR[64];
char tmp[64];
int i,j;
ip(mtext,ll,rr);
for (i=16; i>0; i--)
{
F(i,ll,rr,LL,RR);
for (j=0; j<32; j++)
{
ll[j]=LL[j];
rr[j]=RR[j];
}
}
_ip((unsigned char *)tmp,rr,ll);
compress0(tmp,text);
}
static void expand0(unsigned char *in,char *out)
{
int divide;
int i,j;
for (i=0; i<8; i++)
{
divide=0x80;
for (j=0; j<8; j++)
{
*out++=(in[i]/divide)&1;
divide/=2;
}
}
}
static void compress0(char *out,unsigned char *in)
{
int times;
int i,j;
for (i=0; i<8; i++)
{
times=0x80;
in[i]=0;
for (j=0; j<8; j++)
{
in[i]+=(*out++)*times;
times/=2;
}
}
}
static void setkeystar(unsigned char bits[64])
{
int i,j;
for (i=0; i<28; i++)
C[0][i]=bits[pc_1_c[i]-1];
for (i=0; i<28; i++)
D[0][i]=bits[pc_1_d[i]-1];
for (j=0; j<16; j++)
{
LS((char *)(C[j]),(char *)(C[j+1]),ls_count[j]);
LS((char *)(D[j]),(char *)(D[j+1]),ls_count[j]);
son((char *)(C[j+1]),(char *)(D[j+1]),(char *)(K[j+1]));
}
}
static void LS(char *bits,char *buffer,int count)
{
int i;
for (i=0; i<28; i++)
{
buffer[i]=bits[(i+count)%28];
}
}
static void son(char *cc,char *dd,char *kk)
{
int i;
char buffer[56];
for (i=0; i<28; i++)
buffer[i] = *cc++;
for (i=28; i<56; i++)
buffer[i] = *dd++;
for (i=0; i<48; i++)
*kk++=buffer[pc_2[i]-1];
}
static void ip(unsigned char *text,char *ll,char *rr)
{
int i;
char buffer[64];
expand0(text,buffer);
for (i=0; i<32; i++)
ll[i]=buffer[ip_tab[i]-1];
for (i=0; i<32; i++)
rr[i]=buffer[ip_tab[i+32]-1];
}
static void _ip(unsigned char *text,char *ll,char *rr)
{
int i;
char tmp[64];
for (i=0; i<32; i++)
tmp[i]=ll[i];
for (i=32; i<64; i++)
tmp[i]=rr[i-32];
for (i=0; i<64; i++)
text[i]=tmp[_ip_tab[i]-1];
}
static void F(int n,char *ll,char *rr,char *LL,char *RR)
{
int i;
char tmp1[32], tmp2[32];
char e[48];
for (i = 0; i < 32; i++)
LL[i] = rr[i];
for (i = 0; i < 48; i++)
e[i] = rr[e_r[i]-1];
Do_XOR((unsigned char *)e, (unsigned char *)K[n], 48);
s_box(e, tmp1);
for (i = 0; i < 32; i++)
tmp2[i] = tmp1[P[i]-1];
for (i = 0; i < 32; i++)
RR[i] = ll[i];
Do_XOR((unsigned char *)RR, (unsigned char *)tmp2, 32);
}
static
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