DiffieHellman.java

class DiffieHellman {
public static void main(String args[]) {
int p = 23; /* publicly known (prime number) */
int g = 5; /* publicly known (primitive root) */
int x = 4; /* only Alice knows this secret */
int y = 3; /* only Bob knows this secret */
double aliceSends = (Math.pow(g, x)) % p;
double bobComputes = (Math.pow(aliceSends, y)) % p;
double bobSends = (Math.pow(g, y)) % p;
double aliceComputes = (Math.pow(bobSends, x)) % p;
double sharedSecret = (Math.pow(g, (x * y))) % p;
System.out.println("simulation of Diffie-Hellman key exchange algorithm\n--
 ");
System.out.println("Alice Sends : " + aliceSends);
System.out.println("Bob Computes : " + bobComputes);
System.out.println("Bob Sends : " + bobSends);
System.out.println("Alice Computes : " + aliceComputes);
System.out.println("Shared Secret : " + sharedSecret);
/* shared secrets should match and equality is transitive */
if ((aliceComputes == sharedSecret) && (aliceComputes == bobComputes))
System.out.println("Success: Shared Secrets Matches! " + sharedSecret);
else
System.out.println("Error: Shared Secrets does not Match");
}
}
OUTPUT:
simulation of Diffie-Hellman key exchange algorithm
Alice Sends : 4.0
Bob Computes :
18.0 Bob Sends :
10.0
Alice Computes :
18.0 Shared Secret :
18.0
Success: Shared Secrets Matches! 18.0