?? main.cpp
字號:
/* DES Encryption & Decryption Code */
# include <stdio.h>
# include <fstream.h>
# include <string.h>
# include <conio.h>
# include <iostream.h>
#include <stdlib.h>
int key[64]={
0,0,0,1,0,0,1,1,
0,0,1,1,0,1,0,0,
0,1,0,1,0,1,1,1,
0,1,1,1,1,0,0,1,
1,0,0,1,1,0,1,1,
1,0,1,1,1,1,0,0,
1,1,0,1,1,1,1,1,
1,1,1,1,0,0,0,1
};
class Des
{
public:
int keyi[16][48],
total[64],
left[32],
right[32],
ck[28],
dk[28],
expansion[48],
z[48],
xor1[48],
sub[32],
p[32],
xor2[32],
temp[64],
pc1[56],
ip[64],
inv[8][8];
char final[1000];
void IP();
void PermChoice1();
void PermChoice2();
void Expansion();
void inverse();
void xor_two();
void xor_oneE(int);
void xor_oneD(int);
void substitution();
void permutation();
void keygen();
char * Encrypt(char *);
char * Decrypt(char *);
};
void Des::IP() //Initial Permutation
{
int k=58,i;
for(i=0;i<32;i++)
{
ip[i]=total[k-1];
if(k-8>0) k=k-8;
else k=k+58;
}
k=57;
for( i=32;i<64;i++)
{
ip[i]=total[k-1];
if(k-8>0) k=k-8;
else k=k+58;
}
}
void Des::PermChoice1() //Permutation Choice-1
{
int k=57,i;
for(i=0;i<28;i++)
{
pc1[i]=key[k-1];
if(k-8>0) k=k-8;
else k=k+57;
}
k=63;
for( i=28;i<52;i++)
{
pc1[i]=key[k-1];
if(k-8>0) k=k-8;
else k=k+55;
}
k=28;
for(i=52;i<56;i++)
{
pc1[i]=key[k-1];
k=k-8;
}
}
void Des::Expansion() //Expansion Function applied on `right' half
{
int exp[8][6],i,j,k;
for( i=0;i<8;i++)
{
for( j=0;j<6;j++)
{
if((j!=0)||(j!=5))
{
k=4*i+j;
exp[i][j]=right[k-1];
}
if(j==0)
{
k=4*i;
exp[i][j]=right[k-1];
}
if(j==5)
{
k=4*i+j;
exp[i][j]=right[k-1];
}
}
}
exp[0][0]=right[31];
exp[7][5]=right[0];
k=0;
for(i=0;i<8;i++)
for(j=0;j<6;j++)
expansion[k++]=exp[i][j];
}
void Des::PermChoice2()
{
int per[56],i,k;
for(i=0;i<28;i++) per[i]=ck[i];
for(k=0,i=28;i<56;i++) per[i]=dk[k++];
z[0]=per[13];z[1]=per[16];z[2]=per[10];z[3]=per[23];z[4]=per[0];z[5]=per[4];z[6]=per[2];z[7]=per[27];
z[8]=per[14];z[9]=per[5];z[10]=per[20];z[11]=per[9];z[12]=per[22];z[13]=per[18];z[14]=per[11];z[15]=per[3];
z[16]=per[25];z[17]=per[7];z[18]=per[15];z[19]=per[6];z[20]=per[26];z[21]=per[19];z[22]=per[12];z[23]=per[1];
z[24]=per[40];z[25]=per[51];z[26]=per[30];z[27]=per[36];z[28]=per[46];z[29]=per[54];z[30]=per[29];z[31]=per[39];
z[32]=per[50];z[33]=per[46];z[34]=per[32];z[35]=per[47];z[36]=per[43];z[37]=per[48];z[38]=per[38];z[39]=per[55];
z[40]=per[33];z[41]=per[52];z[42]=per[45];z[43]=per[41];z[44]=per[49];z[45]=per[35];z[46]=per[28];z[47]=per[31];
}
void Des::xor_oneE(int round) //for Encrypt
{
int i;
for(i=0;i<48;i++)
xor1[i]=expansion[i]^keyi[round-1][i];
}
void Des::xor_oneD(int round) //for Decrypt
{
int i;
for(i=0;i<48;i++)
xor1[i]=expansion[i]^keyi[16-round][i];
}
void Des::substitution()
{
int s1[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,
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
};
int s2[4][16]={
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
};
int s3[4][16]={
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
};
int s4[4][16]={
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
};
int s5[4][16]={
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,
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
};
int s6[4][16]={
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
};
int s7[4][16]={
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
};
int s8[4][16]={
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
};
int a[8][6],k=0,i,j,p,q,count=0,g=0,v;
for(i=0;i<8;i++)
{
for(j=0;j<6;j++)
{
a[i][j]=xor1[k++];
}
}
for( i=0;i<8;i++)
{
p=1;q=0;
k=(a[i][0]*2)+(a[i][5]*1);
j=4;
while(j>0)
{
q=q+(a[i][j]*p);
p=p*2;
j--;
}
count=i+1;
switch(count)
{
case 1: v=s1[k][q]; break;
case 2: v=s2[k][q]; break;
case 3: v=s3[k][q]; break;
case 4: v=s4[k][q]; break;
case 5: v=s5[k][q]; break;
case 6: v=s6[k][q]; break;
case 7: v=s7[k][q]; break;
case 8: v=s8[k][q]; break;
}
int d,i=3,a[4];
while(v>0)
{
d=v%2;
a[i--]=d;
v=v/2;
}
while(i>=0)
{
a[i--]=0;
}
for(i=0;i<4;i++)
sub[g++]=a[i];
}
}
void Des::permutation()
{
p[0]=sub[15];p[1]=sub[6];p[2]=sub[19];p[3]=sub[20];p[4]=sub[28];p[5]=sub[11];p[6]=sub[27];p[7]=sub[16];
p[8]=sub[0];p[9]=sub[14];p[10]=sub[22];p[11]=sub[25];p[12]=sub[4];p[13]=sub[17];p[14]=sub[30];p[15]=sub[9];
p[16]=sub[1];p[17]=sub[7];p[18]=sub[23];p[19]=sub[13];p[20]=sub[31];p[21]=sub[26];p[22]=sub[2];p[23]=sub[8];
p[24]=sub[18];p[25]=sub[12];p[26]=sub[29];p[27]=sub[5];p[28]=sub[21];p[29]=sub[10];p[30]=sub[3];p[31]=sub[24];
}
void Des::xor_two()
{
int i;
for(i=0;i<32;i++)
{
xor2[i]=left[i]^p[i];
}
}
void Des::inverse()
{
int p=40,q=8,k1,k2,i,j;
for(i=0;i<8;i++)
{
k1=p;k2=q;
for(j=0;j<8;j++)
{
if(j%2==0)
{
inv[i][j]=temp[k1-1];
k1=k1+8;
}
else if(j%2!=0)
{
inv[i][j]=temp[k2-1];
k2=k2+8;
}
}
p=p-1;q=q-1;
}
}
char * Des::Encrypt(char *Text1)
{
int i,a1,j,nB,m,iB,k,K,B[8],n,t,d,round;
char *Text=new char[1000];
strcpy(Text,Text1);
i=strlen(Text);
int mc=0;
a1=i%8;
if(a1!=0)
for(j=0;j<8-a1;j++,i++)
Text[i]=' ';
Text[i]='\0';
keygen();
for(iB=0,nB=0,m=0;m<(strlen(Text)/8);m++) //Repeat for TextLenth/8 times.
{
for(iB=0,i=0;i<8;i++,nB++)
{
n=(int)Text[nB];
for(K=7;n>=1;K--)
{
B[K]=n%2; //Converting 8-Bytes to 64-bit Binary Format
n/=2;
}
for(;K>=0;K--) B[K]=0;
for(K=0;K<8;K++,iB++)
total[iB]=B[K]; //Now `total' contains the 64-Bit binary format of 8-Bytes
}
IP(); //Performing initial permutation on `total[64]'
for(i=0;i<64;i++) total[i]=ip[i]; //Store values of ip[64] into total[64]
for(i=0;i<32;i++) left[i]=total[i]; // +--> left[32]
// total[64]--|
for(;i<64;i++) right[i-32]=total[i];// +--> right[32]
for(round=1;round<=16;round++)
{
Expansion(); //Performing expansion on `right[32]' to get `expansion[48]'
xor_oneE(round); //Performing XOR operation on expansion[48],z[48] to get xor1[48]
substitution();//Perform substitution on xor1[48] to get sub[32]
permutation(); //Performing Permutation on sub[32] to get p[32]
xor_two(); //Performing XOR operation on left[32],p[32] to get xor2[32]
for(i=0;i<32;i++) left[i]=right[i]; //Dumping right[32] into left[32]
for(i=0;i<32;i++) right[i]=xor2[i]; //Dumping xor2[32] into right[32]
}
for(i=0;i<32;i++) temp[i]=right[i]; // Dumping -->[ swap32bit ]
for(;i<64;i++) temp[i]=left[i-32]; // left[32],right[32] into temp[64]
inverse(); //Inversing the bits of temp[64] to get inv[8][8]
/* Obtaining the Cypher-Text into final[1000]*/
k=128; d=0;
for(i=0;i<8;i++)
{
for(j=0;j<8;j++)
{
d=d+inv[i][j]*k;
k=k/2;
}
final[mc++]=(char)d;
k=128; d=0;
}
} //for loop ends here
final[mc]='\0';
return(final);
}
char * Des::Decrypt(char *Text1)
{
int i,a1,j,nB,m,iB,k,K,B[8],n,t,d,round;
char *Text=new char[1000];
unsigned char ch;
strcpy(Text,Text1);
i=strlen(Text);
keygen();
int mc=0;
for(iB=0,nB=0,m=0;m<(strlen(Text)/8);m++) //Repeat for TextLenth/8 times.
{
for(iB=0,i=0;i<8;i++,nB++)
{
ch=Text[nB];
n=(int)ch;//(int)Text[nB];
for(K=7;n>=1;K--)
{
B[K]=n%2; //Converting 8-Bytes to 64-bit Binary Format
n/=2;
} for(;K>=0;K--) B[K]=0;
for(K=0;K<8;K++,iB++) total[iB]=B[K]; //Now `total' contains the 64-Bit binary format of 8-Bytes
}
IP(); //Performing initial permutation on `total[64]'
for(i=0;i<64;i++) total[i]=ip[i]; //Store values of ip[64] into total[64]
for(i=0;i<32;i++) left[i]=total[i]; // +--> left[32]
// total[64]--|
for(;i<64;i++) right[i-32]=total[i];// +--> right[32]
for(round=1;round<=16;round++)
{
Expansion(); //Performing expansion on `right[32]' to get `expansion[48]'
xor_oneD(round);
substitution();//Perform substitution on xor1[48] to get sub[32]
permutation(); //Performing Permutation on sub[32] to get p[32]
xor_two(); //Performing XOR operation on left[32],p[32] to get xor2[32]
for(i=0;i<32;i++) left[i]=right[i]; //Dumping right[32] into left[32]
for(i=0;i<32;i++) right[i]=xor2[i]; //Dumping xor2[32] into right[32]
} //rounds end here
for(i=0;i<32;i++) temp[i]=right[i]; // Dumping -->[ swap32bit ]
for(;i<64;i++) temp[i]=left[i-32]; // left[32],right[32] into temp[64]
inverse(); //Inversing the bits of temp[64] to get inv[8][8]
/* Obtaining the Cypher-Text into final[1000]*/
k=128; d=0;
for(i=0;i<8;i++)
{
for(j=0;j<8;j++)
{
d=d+inv[i][j]*k;
k=k/2;
}
final[mc++]=(char)d;
k=128; d=0;
}
} //for loop ends here
final[mc]='\0';
char *final1=new char[1000];
for(i=0,j=strlen(Text);i<strlen(Text);i++,j++)
final1[i]=final[j]; final1[i]='\0';
return(final);
}
void main()
{
Des d1,d2;
char *str=new char[1000];
char *str1=new char[1000];
char *str2=new char[1000];
//clrscr();
//strcpy(str,"PHOENIX it & ece solutions.");
cout<<"Enter a string : "<<endl;
gets(str);
str1=d1.Encrypt(str);
cout<<"\ni/p Text: "<<str<<endl;
cout<<"\nCypher : "<<str1<<endl;
//ofstream fout("out2_fil.txt"); fout<<str1; fout.close();
str2=d2.Decrypt(str1);
cout<<"\no/p Text: "<<str2<<endl;
//getch();
}
void Des::keygen()
{
PermChoice1();
int i,j,k=0;
for(i=0;i<28;i++)
{
ck[i]=pc1[i];
}
for(i=28;i<56;i++)
{
dk[k]=pc1[i];
k++;
}
int noshift=0,round;
for(round=1;round<=16;round++)
{
if(round==1||round==2||round==9||round==16)
noshift=1;
else
noshift=2;
while(noshift>0)
{
int t;
t=ck[0];
for(i=0;i<28;i++)
ck[i]=ck[i+1];
ck[27]=t;
t=dk[0];
for(i=0;i<28;i++)
dk[i]=dk[i+1];
dk[27]=t;
noshift--;
}
PermChoice2();
for(i=0;i<48;i++)
keyi[round-1][i]=z[i];
}
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