To implement S-DES sub key Generation in C. (WITH OUTPUT IMAGE)

#include<stdio.h>

#include<conio.h>

void main()

{

//sub key generation.

char key[10];

int k[10],k10[10],k8[10],p10[10]={3,5,2,7,4,10,1,9,8,6},temp,temp1;

int p8[8]={6,3,7,4,8,5,10,9},i,j,l0[5],r0[5],l1[5],r1[5];

int k1[8],k2[8];

clrscr();

abs:

printf("P10=3,5,2,7,4,10,1,9,8,6");

printf("\nP8=6,3,7,4,8,5,10,9");

printf("\n Enter 10 bit key:: ");

gets(key);

//149 for 1 and 48 for 0.

if(strlen(key)!=10)

goto abs;

for(i=0;i<10;i++)

{if(key[i]=='1')

 k[i]=1;

 else if(key[i]=='0')

 k[i]=0;

 else

 goto abs;

}

for(i=0;i<10;i++)

printf("%d",k[i]);

//p10 operation.

printf("\n Result of p10::");

for(i=0;i<10;i++)

{k10[i]=k[p10[i]-1];

printf("%d",k10[i]);

}

//devide in two parts.

for(i=0;i<5;i++)

{l0[i]=k10[i];

 r0[i]=k10[i+5];

}

printf("\n L-part::");

for(i=0;i<5;i++)

printf("%d",l0[i]);

printf("\n R-part::");

for(i=0;i<5;i++)

printf("%d",r0[i]);

//apply 1 shift on both parts.

printf("\n after 1bit right shift");

for(i=0;i<5;i++)

{

l1[i]=l0[i+1];

r1[i]=r0[i+1];

if(i==4)

{l1[i]=l0[0];

r1[i]=r1[0];

}

}

printf("\n L1::");

for(i=0;i<5;i++)

printf("%d",l1[i]);

printf("\n R1::");

for(i=0;i<5;i++)

printf("%d",r1[i]);

//combine  L1 & R1.

for(i=0;i<5;i++)

{ k8[i]=l1[i];

  k8[i+5]=r1[i];

}

printf("\n combined L1 || R1::");

for(i=0;i<10;i++)

printf("%d",k8[i]);

//do p8 on 8-bit key;

printf("\n K1::");

for(i=0;i<8;i++)

printf("%d",k1[i]=k8[p8[i]-1]);

//K1 calculated.

//for K2 use combined l0 & r0 =k8.

for(i=0;i<5;i++)

{l1[i]=k8[i];

r1[i]=k8[i+5];

}

printf("\n \n");

//now apply p8 on both parts.

printf("\n L1::");

for(i=0;i<5;i++)

printf("%d",l1[i]);

printf("\n R1::");

for(i=0;i<5;i++)

printf("%d",r1[i]);

printf("\n after 2 right shift operation;:");

for(j=0;j<2;j++)

{

 for(i=0;i<4;i++)

 {temp=l1[i];

  l1[i]=l1[i+1];

  l1[i+1]=temp;

  temp1=r1[i];

  r1[i]=r1[i+1];

  r1[i+1]=temp1;

 }

}

printf("\nL2::");

for(i=0;i<5;i++)

printf("%d",l1[i]);

printf("\nR2::");

for(i=0;i<5;i++)

printf("%d",r1[i]);

for(i=0;i<5;i++)

{

k8[i]=l1[i];

k8[i+5]=r1[i];

}

printf("\n L2 || R2::");

for(i=0;i<10;i++)

printf("%d",k8[i]);

//p8 operaion.

printf("\n After p8 operation on combined bits \n K2::");

for(i=0;i<8;i++)

printf("%d",k2[i]=k8[p8[i]-1]);

getch();

}

OUTPUT: