multiplication_cipher

//package multiplication;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.lang.String;
import javax.swing.*;
public class Multi {
    static String alp = "abcdefghijklmnopqrstuvwxyz";
    static int[] dgt0 = {1, 3, 5, 7, 9, 11, 15, 17, 19, 21, 23, 25};
    static int[] dgt1 = {1, 9, 21, 15, 3, 19, 7, 23, 11, 5, 17, 25};
    public static void main(String[] args) {
        JFrame frame = new JFrame("Mixed");
        frame.setLayout(new GridLayout(4, 2));
        frame.setSize(500, 150);
        JTextField plaintext = new JTextField();
        JTextField kln = new JTextField();
        JLabel plaintxt = new JLabel("Plaintext");
        JLabel klen = new JLabel("K");
        JLabel encrypted = new JLabel("Encrypted");
        JLabel decrypted = new JLabel("Decrypted");
        JButton encrypt = new JButton("Encrypt");
        JButton decrypt = new JButton("Decrypt");
        frame.add(plaintxt);
        frame.add(plaintext);
        frame.add(klen);
        frame.add(kln);
        frame.add(encrypt);
        frame.add(encrypted);
        frame.add(decrypt);
        frame.add(decrypted);
        frame.setVisible(true);
        encrypt.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                // TODO Auto-generated method stub
                int k = Integer.parseInt(kln.getText());
                String cipher = "";
                char tmp;
                int tmp2;
                for (int i = 0; i < plaintext.getText().length(); ++i) {
                    tmp = plaintext.getText().charAt(i);
                    tmp2 = (alp.indexOf(tmp) * k) % 26;
                    cipher += alp.charAt(tmp2);
                }
                encrypted.setText(cipher);
            }
        });
        decrypt.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {
                String dec = "";
                String cipher = encrypted.getText().toString();
                char tmp;
                int tmp2;
                int k = Integer.parseInt(kln.getText());
                for(int i = 0; i<dgt0.length; ++i) {
                    if(k == dgt0[i]) {
                        k = dgt1[i];
                        break;
                    }
                }
                for (int i = 0; i < cipher.length(); ++i) {
                    tmp = cipher.charAt(i);
                    tmp2 = (alp.indexOf(tmp) * k) % 26;
                    dec += alp.charAt(tmp2);
                }
                decrypted.setText(dec);
            }
        });
    }
}