public class username extends javax.swing.JPanel {

/**
 * Creates new form username
 */
public username() {
    initComponents();
}

/**
 * This method is called from within the constructor to initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is always
 * regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">//GEN-BEGIN:initComponents
private void initComponents() {

    jLabel1 = new javax.swing.JLabel();
    jLabel2 = new javax.swing.JLabel();
    jTextField1 = new javax.swing.JTextField();
    jTextField2 = new javax.swing.JTextField();
    OK = new java.awt.Button();

    jLabel1.setText("Username");

    jLabel2.setText("PIN");

    OK.setActionCommand("OK");
    OK.setFont(new java.awt.Font("Calibri", 1, 14)); // NOI18N
    OK.setLabel("OK");
    ClickListener cl = new ClickListener();
    OK.addActionListener(cl);

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
    this.setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(107, 107, 107)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addComponent(jLabel1)
                    .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                    .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 144, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGroup(layout.createSequentialGroup()
                    .addComponent(jLabel2)
                    .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                        .addGroup(layout.createSequentialGroup()
                            .addGap(72, 72, 72)
                            .addComponent(OK, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                        .addGroup(layout.createSequentialGroup()
                            .addGap(41, 41, 41)
                            .addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, 161, javax.swing.GroupLayout.PREFERRED_SIZE)))))
            .addContainerGap(74, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(55, 55, 55)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jLabel1)
                .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
            .addGap(18, 18, 18)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                .addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addComponent(jLabel2))
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 90, Short.MAX_VALUE)
            .addComponent(OK, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(72, 72, 72))
    );
    this.setSize(400,250);
}// </editor-fold>//GEN-END:initComponents

    class ClickListener implements ActionListener
{
    @Override
    public void actionPerformed(ActionEvent e)
    {
        if("OK".equals(e.getActionCommand()))
        {
            try
            {
                String username = jTextField1.getText();
                System.out.println(username);
                if (username.length() == 0)
                {
                    JOptionPane.showMessageDialog(username.this, "You did not enter a username!", "Username", JOptionPane.INFORMATION_MESSAGE);
                }
                String pintest = jTextField2.getText();
                if (pintest.length() != 4)
                {
                    JOptionPane.showMessageDialog(username.this, "Your PIN consists of 4 digits", "PIN", JOptionPane.INFORMATION_MESSAGE);
                }
                LocalTime now = LocalTime.now();
                int minutes = now.getMinute();
                System.out.println(minutes);
                String minstring = Integer.toString(minutes);
                System.out.println(minstring);
                pintest = pintest.concat(minstring);
                System.out.println(pintest);
                MessageDigest messageDigest=null;
                try
                {
                    messageDigest = MessageDigest.getInstance("SHA-256");
                    messageDigest.update((pintest).getBytes());
                }
                catch (NoSuchAlgorithmException f)
                {
                }
                @SuppressWarnings("null")
                        String encryptedPassword = (new BigInteger(messageDigest.digest())).toString(16);
                System.out.println("Encrypted Password: " + encryptedPassword);
                String hashed = encryptedPassword.substring(0, 8);
                System.out.println(hashed);
                PublicKey publicKey = readPublicKey("public.der");
                PrivateKey privateKey = readPrivateKey("private.der");
                byte[] message = hashed.getBytes("UTF8");
                byte[] secret = encrypt(publicKey, message);
                byte[] recovered_message = decrypt(privateKey, secret);
                System.out.println(new String(message, "UTF8"));
                System.out.println(new String(recovered_message, "UTF8"));

            }
            catch (HeadlessException | IOException | NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | IllegalBlockSizeException | BadPaddingException g)
            {
            } catch (InvalidKeySpecException ex) {
                Logger.getLogger(username.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }

    public PublicKey readPublicKey(String filename) throws IOException, NoSuchAlgorithmException, InvalidKeySpecException
    {
        byte[] keyBytes = Files.readAllBytes(new File(filename).toPath());
        X509EncodedKeySpec publicSpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        return keyFactory.generatePublic(publicSpec);
    }
    public PrivateKey readPrivateKey(String filename) throws IOException, NoSuchAlgorithmException, InvalidKeySpecException
    {
        byte[] keyBytes1 = Files.readAllBytes(new File(filename).toPath());
        PKCS8EncodedKeySpec privateSpec = new PKCS8EncodedKeySpec(keyBytes1);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        return keyFactory.generatePrivate(privateSpec);
    }
    public byte[] encrypt(PublicKey key, byte[] plaintext) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException
    {
        Cipher cipher = Cipher.getInstance("RSA/ECB/OAEPWithSHA1AndMGF1Padding");
        cipher.init(Cipher.ENCRYPT_MODE, key);
        return cipher.doFinal(plaintext);
    }
    public byte[] decrypt(PrivateKey key, byte[] ciphertext) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException
    {
        Cipher cipher = Cipher.getInstance("RSA/ECB/OAEPWithSHA1AndMGF1Padding");
        cipher.init(Cipher.DECRYPT_MODE, key);
        return cipher.doFinal(ciphertext);
    }
}

// Variables declaration - do not modify//GEN-BEGIN:variables
private int minutes;
private String minstring, pintest, hashed;
private java.awt.Button OK;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JTextField jTextField1;
private javax.swing.JTextField jTextField2;
// End of variables declaration//GEN-END:variables