aJy9bDfp

1import java.math.*;
2import java.util.*;
3import java.security.*;
4import java.io.*;
5public class elgamel
6{
7    public static void main(String[] args) throws IOException
8    {
9        BigInteger p, b, c, secretKey;
10
11        Scanner ssc=new Scanner(System.in);
12        Random sc = new SecureRandom();
13        secretKey = new BigInteger("12345678901234567890");
14       //Calculating Public key
15        System.out.println("secretKey = " + secretKey);
16        p = BigInteger.probablePrime(64, sc);
17        b = new BigInteger("3");
18        c = b.modPow(secretKey, p);
19        System.out.println("p = " + p);
20        System.out.println("b = " + b);
21        System.out.println("c = " + c);
22        //Input
23        System.out.print("Enter the 3x3 image matrix to encrypt");
24
25        String s[][]= new String[3][3];
26        for(int i=0;i<3;i++)
27        {
28            for(int j=0;j<3;j++)
29            {
30                s[i][j]=ssc.nextLine();
31            }
32        }
33         for(int i=0;i<3;i++)
34        {
35            for(int j=0;j<3;j++)
36            {
37                //Encryption
38                 BigInteger X = new BigInteger(s[i][j]);
39                 BigInteger r = new BigInteger(64, sc);
40                 BigInteger EC = X.multiply(c.modPow(r, p)).mod(p);
41                 BigInteger brmodp = b.modPow(r, p);
42                 System.out.println("Plaintext = " + X);
43                 //System.out.println("r = " + r);
44                System.out.println("Encrypted msg = " + EC);
45                System.out.println("b^r mod p = " + brmodp);
46                //Decryption
47                BigInteger crmodp = brmodp.modPow(secretKey, p);
48                  BigInteger d = crmodp.modInverse(p);
49               BigInteger dec = d.multiply(EC).mod(p);
50              System.out.println("\n\nc^r mod p = " + crmodp);
51             //System.out.println("d = " + d);
52             System.out.println("Decrypted msg " + dec);
53            }
54            System.out.println();
55        }
56
57    }
58}