C source file of program
#include<stdio.h>
long int power(int a,int b,int mod)
{
long int t;
if(b==1)
return a;
t=power(a,b/2,mod);
if(b%2==0)
return (t*t)%mod;
else
return (((t*t)%mod)*a)%mod;
}
longlongintcalculateKey(int a,int x,int n)
{
return power(a,x,n);
}
void main()
{
int n,g,x,a,y,b;
clrscr();
printf("Enter the value of n and g : ");
scanf("%d%d",&n,&g);
// first person will choose the x
printf("Enter the value of x for the first person : ");
scanf("%d",&x); a=power(g,x,n);
// second person will choose the y
printf("Enter the value of y for the second person : ");
scanf("%d",&y); b=power(g,y,n);
printf("key for the first person is : %lld\n",power(b,x,n));
printf("key for the second person is : %lld\n",power(a,y,n));
getch();
}
Output :
