elgamal.java

ElGamal算法

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.io.*;
import java.math.*;

public class ElGamal extends JInternalFrame implements ActionListener
{
	// Parameters Begin
	private JTextField bTextField;
	private JTextField cTextField;
	private JTextField pTextField;
	private JTextField rTextField;
		// Parameters End

	private JButton encryptButton, decryptButton, loadButton, saveButton;
	private JTextArea inputTextArea, outputTextArea;
	private JPanel parameterPanel, textPanel, inputPanel, outputPanel, topInputPanel, topOutputPanel;
	private Container mainContainer;
	private final int width=400, height=600;
	private boolean casechange=false, clean=false;

	public ElGamal()
	{
		super("ElGamal Cipher", true, true, true, true);

		mainContainer = getContentPane();
		mainContainer.setLayout(new BorderLayout(0,0));

		// Parameter Panel Begin

		bTextField = new JTextField(5);
		cTextField = new JTextField(5);
		pTextField = new JTextField(5);
		rTextField = new JTextField(5);

		parameterPanel = new JPanel();
		parameterPanel.add(new JLabel("b="));
		parameterPanel.add(bTextField);
		parameterPanel.add(new JLabel("c="));
		parameterPanel.add(cTextField);
		parameterPanel.add(new JLabel("p="));
		parameterPanel.add(pTextField);
		parameterPanel.add(new JLabel("r="));
		parameterPanel.add(rTextField);



		// Parameter Panel End / Input Panel Begin

		loadButton = new JButton("Load");
		loadButton.addActionListener(this);

		topInputPanel = new JPanel();
		topInputPanel.add(new JLabel("Enter text or "));
		topInputPanel.add(loadButton);

		inputTextArea = new JTextArea();
		inputTextArea.setAutoscrolls(true);
		inputTextArea.setLineWrap(true);
		inputTextArea.setWrapStyleWord(true);

		inputPanel = new JPanel();
		inputPanel.setLayout(new BorderLayout(0,0));

		inputPanel.add(topInputPanel,BorderLayout.NORTH);
		inputPanel.add(new JScrollPane(inputTextArea, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER),BorderLayout.CENTER);

		// Input Panel End / Output Panel Begin

		encryptButton = new JButton("Encrypt");
		encryptButton.addActionListener(this);
		decryptButton = new JButton("Decrypt");
		decryptButton.addActionListener(this);
		saveButton = new JButton("Save");
		saveButton.addActionListener(this);

		topOutputPanel = new JPanel();
		topOutputPanel.add(encryptButton);
		topOutputPanel.add(new JLabel(" or "));
		topOutputPanel.add(decryptButton);
		topOutputPanel.add(new JLabel(" or "));
		topOutputPanel.add(saveButton);

		outputTextArea = new JTextArea();
		outputTextArea.setAutoscrolls(true);
		outputTextArea.setLineWrap(true);
		outputTextArea.setWrapStyleWord(true);
		outputTextArea.setEditable(false);

		outputPanel = new JPanel();
		outputPanel.setLayout(new BorderLayout(0,0));

		outputPanel.add(topOutputPanel,BorderLayout.NORTH);
		outputPanel.add(new JScrollPane(outputTextArea, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER),BorderLayout.CENTER);

		// Output Panel End

		textPanel = new JPanel();
		textPanel.setLayout(new GridLayout(2,1));

		textPanel.add(inputPanel);
		textPanel.add(outputPanel);

		mainContainer.add(parameterPanel, BorderLayout.NORTH);
		mainContainer.add(textPanel, BorderLayout.CENTER);

		setSize(width,height);
		setLocation(450,0);
		show();
	}

	public String cleanString(String toClean)
	{
		String returnString = new String();

		for(int i=0;i<toClean.length();i++)
		{
			if (Character.isLetter(toClean.charAt(i)) == true)
				returnString = returnString + toClean.charAt(i);
		}

		return returnString;
	}

	public void actionPerformed(ActionEvent e)
	{
		outputTextArea.setText("");
		if (e.getSource()==encryptButton)
		{
			String toEncrypt = new String(inputTextArea.getText());

			BigInteger B = new BigInteger(bTextField.getText());
			BigInteger C = new BigInteger(cTextField.getText());
			BigInteger P = new BigInteger(pTextField.getText());
			BigInteger R = new BigInteger(rTextField.getText());
			BigInteger Q = new BigInteger("0");
			BigInteger Y = new BigInteger("0");
			Q = P.subtract(BigInteger.ONE);
			System.out.println(B.modPow(Q,P).intValue());
			if (B.modPow(Q,P).intValue()!=1)
				outputTextArea.setText("B is not a near primitive root of P");
			else
			{
				if(toEncrypt.length()%2!=0);
					toEncrypt = toEncrypt + "0";

				char charArray[] = toEncrypt.toCharArray();
				String s = new String();

				for(int i=0;i<toEncrypt.length()-1;i+=2)
				{
					BigInteger X = new BigInteger(""+(((int)charArray[i]-48)*10+(int)charArray[i+1]-48));
					Y = X.multiply(C.pow(R.intValue()));
					Y = Y.mod(P);
					s = s + Y.toString() + ", ";
				}
				char charAr[] = s.toCharArray();
				charAr[s.length()-1] = ' ';
				charAr[s.length()-2] = ' ';



				outputTextArea.setText(new String(charAr));
			}
		}

		else if (e.getSource()==decryptButton)
		{
			String toDecrypt = new String(inputTextArea.getText());

			BigInteger B = new BigInteger(bTextField.getText());
			BigInteger C = new BigInteger(cTextField.getText());
			BigInteger P = new BigInteger(pTextField.getText());
			BigInteger R = new BigInteger(rTextField.getText());
			BigInteger Q = new BigInteger("0");
			BigInteger Y = new BigInteger("0");
			String s = new String();

			char charArray[] = toDecrypt.toCharArray();
			StringTokenizer st = new StringTokenizer(inputTextArea.getText(), "();., ");
				while (st.hasMoreTokens())
				{
					BigInteger V = new BigInteger(st.nextToken());
					Q= C.modPow(R,P);
					Q= Q.modInverse(P);
					Q = V.multiply(Q).mod(P);
					if (Q.toString().length()==1)
						s = s + "0" + Q.toString();
					else
						s = s + Q.toString();
				}
			outputTextArea.setText(s);
		}

		else if (e.getSource()==loadButton)
		{
			JFileChooser fileChooser = new JFileChooser();
			JOptionPane optionPane;
			BufferedReader file;
			int dialogvalue;
			String temp;

			try
			{
				dialogvalue = fileChooser.showOpenDialog(mainContainer);
				repaint();
				if (dialogvalue == fileChooser.CANCEL_OPTION || dialogvalue == fileChooser.ERROR_OPTION)
				{
					optionPane = new JOptionPane();
					optionPane.showMessageDialog(mainContainer, "File not loaded.");
				}
				else
				{
					file = new BufferedReader(new FileReader(fileChooser.getSelectedFile()));
					inputTextArea.setText("");
					while ((temp = file.readLine()) != null)
						inputTextArea.setText(inputTextArea.getText()+temp+"\n");
					file.close();
				}
			}
			catch (Exception ex)
			{
				optionPane = new JOptionPane();
				optionPane.showMessageDialog(mainContainer, "Error!");
			};
		}

		else if (e.getSource() == saveButton)
		{
			JFileChooser fileChooser = new JFileChooser();
			JOptionPane optionPane;
			BufferedWriter file;
			int dialogvalue;

			try
			{
				dialogvalue = fileChooser.showOpenDialog(mainContainer);
				repaint();
				if (dialogvalue == fileChooser.CANCEL_OPTION || dialogvalue == fileChooser.ERROR_OPTION)
				{
					optionPane = new JOptionPane();
					optionPane.showMessageDialog(mainContainer, "File not loaded.");
				}
				else
				{
					file = new BufferedWriter(new FileWriter(fileChooser.getSelectedFile()));
					file.write(outputTextArea.getText());
					file.close();
				}
			}
			catch (Exception ex)
			{
				optionPane = new JOptionPane();
				optionPane.showMessageDialog(mainContainer, "Error!");
			};
		}

	}

	
}