HillCipherEncrypt.java

import java.io.*;
import java.lang.*;

public class Main {
	public static void main(String[] arg) throws Exception {
		int k[][] = { { 2,1 }, { 3,4 } };
		int p[] = new int[300];
		int c[] = new int[300];
		int i = 0;

		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

		System.out.println("enter plain text");
		String str = br.readLine();

		for (i = 0; i < str.length(); i++) {
			int c1 = str.charAt(i);

			p[i] = c1 - 97;
		}
		i = 0;
		int zz = 0;
		for (int b = 0; b < str.length() / 2; b++) {
			for (int j = 0; j < 2; j++) {
				for (int x = 0; x < 2; x++) {
					c[i] += k[j][x] * p[x + zz];
				}
				i++;
			}
			zz += 2;
		}
		System.out.println("Encrypted Text : ");
		for (int z = 0; z < str.length(); z++)
			System.out.print((char) ((c[z] % 26) + 97));


	}
}