Applet implementation to code Caesar’s substitution cipher

Haider al-Khateeb — Wed, 16 Mar 2011 01:04:05 +0000

In cryptography, Caesar cipher is one of the simplest encryption techniques. It is a substitution cipher in which each letter in the plaintext is replaced by a letter after a fixed number of positions down the alphabet. However, this applet shifts each character (letter, number of symbol) after a number of positions down the ASCII table. Caesar’s cipher is categorised as a symmetric encryption and the secret key in this case is the number of shifts!

To encrypt, select the encode mode, number of shifts and click Run.

You may encode a message multiple times.

To Decrypt, select the decode mode and reverse your steps.

Cannot run Applet!
You do not have Java 2 JDK, Standard Edition v 1.5.0_05 support for APPLET!!

IMPORTANT NOTICE: please note that I did not sign this applet so you may not be able to copy/paste text between the applet and your computer. To read more about this issue I posted another blog called: Creating an executable jar file for an applet.
If you like this piece of software, download the applet to your computer from here (executable jar file). Running the software on your system will solve the copy/paste problem. To successfully execute jar files on your system, you -of course- need to have the Java Runtime Environment (JRE) installed. If you still can not run the jar file, use the ‘Open with’ option and select javax.exe (javax.exe is located inside the bin directory of your JRE folder e.g. C:\Program Files\Java\jre6\bin).

Further, here is the source code I developed for this applet for you to check and compile if you are interested.

/*
 * CaesarCode.java
 *
 * By Haider al-Khateeb (http://blog.creativeitp.com)
 * Created on Mar 14, 2011.
 */
 
package CaesarCodePackage;
 
import javax.swing.JOptionPane;
 
public class CaesarCode extends javax.swing.JApplet {
 
    private String inputText;
	private char [] inputTextChr;
	private int [] inputTextInt;
	private char [] outputTextChr;
	private String intArray = "";
	private String cipher = "";
	private String plain = "";
 
	public static String newLine = System.getProperty("line.separator");
 
             public void inputText(String inputText)
	{
		this.inputText = inputText;
	}
 
	public String getinputText()
	{
		return inputText;
	}
 
	public void convertToChar()
        {
		inputTextChr = inputText.toCharArray();
	}
 
	public void convertCharToInt()
        {
		inputTextInt = new int[inputTextChr.length];
		for (int i=0;i<inputTextChr.length;i++)
                    {
			int inputTextInt2 = (int) inputTextChr[i];
			inputTextInt[i] = inputTextInt2;
                    }
	}
 
 
	public String getIntArray(){
		for (int i=0;i<inputTextInt.length;i++)
                    {
			intArray += inputTextInt[i] + ", ";
                    }
		return intArray;
	}
 
	public String encrypt(int shift)
        {
		for (int i=0;i<inputTextInt.length;i++)
                        {
 
			if ((inputTextInt[i]+shift)> 126)
			{
				inputTextInt[i] =((shift-(126-inputTextInt[i]))+31);
			}
 
			else {	inputTextInt[i] += shift;
			}
 
			}
		outputTextChr = new char[inputTextInt.length];
		for (int i=0;i<outputTextChr.length;i++){
			char outputTextChr2 = (char) inputTextInt[i];
			outputTextChr[i] = outputTextChr2;
                        }
		for (int i=0;i<outputTextChr.length;i++){
			cipher += outputTextChr[i];
			}
		return cipher;
	}
 
	public String decrypt(int shift){
		for (int i=0;i<inputTextInt.length;i++)
                {
			if ((inputTextInt[i]-shift)< 32)
			{
				inputTextInt[i] =(127-(shift-(inputTextInt[i]-32)));
			}
 
			else { inputTextInt[i] -= shift; }
			}
		outputTextChr = new char[inputTextInt.length];
		for (int i=0;i<outputTextChr.length;i++){
			char outputTextChr2 = (char) inputTextInt[i];
			outputTextChr[i] = outputTextChr2;
                    }
		for (int i=0;i<outputTextChr.length;i++){
			plain += outputTextChr[i];
			}
		return plain;
	}
 
 
    /** Initializes the applet CaesarCode */
    public void init() {
        try {
            java.awt.EventQueue.invokeAndWait(new Runnable() {
                public void run() {
                    initComponents();
                }
            });
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
 
    /** This method is called from within the init() method to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // //GEN-BEGIN:initComponents
    private void initComponents() {
 
        jPanel1 = new javax.swing.JPanel();
        jLabel1 = new javax.swing.JLabel();
        jScrollPane1 = new javax.swing.JScrollPane();
        jTextArea1 = new javax.swing.JTextArea();
        jComboBox1 = new javax.swing.JComboBox();
        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        jScrollPane2 = new javax.swing.JScrollPane();
        jList1 = new javax.swing.JList();
        jButton1 = new javax.swing.JButton();
        jButton2 = new javax.swing.JButton();
        jButton3 = new javax.swing.JButton();
        jButton4 = new javax.swing.JButton();
        jButton5 = new javax.swing.JButton();
 
        jPanel1.setBackground(new java.awt.Color(102, 204, 255));
        jPanel1.setBorder(javax.swing.BorderFactory.createEtchedBorder(new java.awt.Color(102, 255, 255), null));
 
        jLabel1.setText("Input your message in the following box");
 
        jTextArea1.setColumns(20);
        jTextArea1.setLineWrap(true);
        jTextArea1.setRows(5);
        jTextArea1.setWrapStyleWord(true);
        jScrollPane1.setViewportView(jTextArea1);
 
        jComboBox1.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "Encode", "Decode" }));
 
        jLabel2.setText("Select mode");
 
        jLabel3.setHorizontalAlignment(javax.swing.SwingConstants.RIGHT);
        jLabel3.setText("Number of shifts");
 
        jList1.setModel(new javax.swing.AbstractListModel() {
            String[] strings = { "01", "02", "03", "04", "05", "06", "07", "08", "09", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "30", "31", "32", "33", "34", "35", "36", "37", "38", "39", "40", "41", "42", "43", "44", "45", "46", "47", "48", "49", "50" };
            public int getSize() { return strings.length; }
            public Object getElementAt(int i) { return strings[i]; }
        });
        jList1.setSelectionMode(javax.swing.ListSelectionModel.SINGLE_SELECTION);
        jList1.setVisibleRowCount(3);
        jScrollPane2.setViewportView(jList1);
 
        jButton1.setText("Run");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });
 
        jButton2.setText("Help?");
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton2ActionPerformed(evt);
            }
        });
 
        jButton3.setText("Copy");
        jButton3.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton3ActionPerformed(evt);
            }
        });
 
        jButton4.setText("Paste");
        jButton4.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton4ActionPerformed(evt);
            }
        });
 
        jButton5.setText("Select All");
        jButton5.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton5ActionPerformed(evt);
            }
        });
 
        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(19, 19, 19)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addComponent(jButton2)
                        .addGap(57, 57, 57)
                        .addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 58, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(29, 29, 29))
                    .addComponent(jScrollPane1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 348, Short.MAX_VALUE)
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
                        .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 87, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(8, 8, 8))
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addGap(12, 12, 12)
                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                            .addGroup(jPanel1Layout.createSequentialGroup()
                                .addComponent(jButton3)
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                                .addComponent(jButton4)
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                                .addComponent(jButton5))
                            .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 278, javax.swing.GroupLayout.PREFERRED_SIZE)
                            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
                                .addGap(74, 74, 74)
                                .addComponent(jLabel3, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                                .addGap(45, 45, 45)
                                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                                    .addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                                    .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 71, javax.swing.GroupLayout.PREFERRED_SIZE))))
                        .addGap(58, 58, 58)))
                .addGap(27, 27, 27))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(jLabel3))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jButton2)
                    .addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(16, 16, 16)
                .addComponent(jLabel1)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jButton3, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(jButton4, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addComponent(jButton5, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 188, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jButton1)
                .addContainerGap())
        );
 
        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
    }// //GEN-END:initComponents
 
    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton1ActionPerformed
        // TODO add your handling code here:
          if (jList1.getSelectedIndex() > -1)
             {
		CaesarCode msg = new CaesarCode();
		msg.inputText(jTextArea1.getText());
		msg.convertToChar(); //convert plain text string to char data type
		msg.convertCharToInt(); // convert char to their equivalent integer (decimal number) in the ASCCI table
		//msg.getIntArray(); // show decimal numbers of the inputText
		int shift = 1 + jList1.getSelectedIndex();
			  if (jComboBox1.getSelectedItem() == "Encode")
			  {
                                jTextArea1.setText(msg.encrypt(shift));
                                //  msg.encrypt(shift) = encrypt and output cipher
			  }
			   else
			  {
				jTextArea1.setText(msg.decrypt(shift));
                                  //  msg.encrypt(shift) = decrypt and output cipher
			  }
		}
		else
                {
                    JOptionPane.showMessageDialog(null, "Please select a number of shifts first!");
		 }
    }//GEN-LAST:event_jButton1ActionPerformed
 
    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton2ActionPerformed
        // TODO add your handling code here:
        JOptionPane.showMessageDialog(null, "To encrypt, select the encode mode, the number of shifts and click ‘Run’." + newLine +
                                            "You may encode the same message multiple times." + newLine +
                                            "To Decrypt, select the decode mode and reverse your encryption steps." + newLine + newLine +
                                            "By Haider al-Khateeb (http://blog.creativeitp.com)");
    }//GEN-LAST:event_jButton2ActionPerformed
 
    private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton3ActionPerformed
        // TODO add your handling code here:
        jTextArea1.copy();
    }//GEN-LAST:event_jButton3ActionPerformed
 
    private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton4ActionPerformed
        // TODO add your handling code here:
        jTextArea1.paste();
    }//GEN-LAST:event_jButton4ActionPerformed
 
    private void jButton5ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton5ActionPerformed
        // TODO add your handling code here:
        jTextArea1.selectAll();
    }//GEN-LAST:event_jButton5ActionPerformed
 
 
    // Variables declaration - do not modify//GEN-BEGIN:variables
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JButton jButton3;
    private javax.swing.JButton jButton4;
    private javax.swing.JButton jButton5;
    private javax.swing.JComboBox jComboBox1;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JList jList1;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JScrollPane jScrollPane2;
    private javax.swing.JTextArea jTextArea1;
    // End of variables declaration//GEN-END:variables
 
}

The pigpen cipher aka Masonic cipher

Haider al-Khateeb — Sun, 11 Jan 2009 08:16:17 +0000

Have you seen a code similar to this before?

An interesting example from real life is the stone of James Leeson, who died in 1792. For a long time, the box-and-dot code at the top of the stone (Figure 1) remained a mystery for the public, but the secret was revealed as Meyer Berger explained in his NY Times column in the 1950s, it was finally decrypted. It says: “Remember death”. It was a Masonic cipher.

Figure 1: Stone of James Leeson 1

The pigpen cipher or the Masonic/Freemason’s cipher is a simple encryption scheme used in the 16th century to secure correspondence between the Freemasons members. [2][3]

The cipher is created by replacing each letter of the alphabet with a symbol, therefore it is defined nowadays as a simple substitution cipher.

Symbols used in pigpen are created by drawing a grid like the one in Figure 2.

Figure 2: A typical example for a pigpen cipher key.

Based on the key (grid) in Figure 2

A sentence like “FREE WORLD” can be encrypted to be:

Fun exercise:

Question: Who was behind the invention of the frequency analysis technique for breaking monoalphabetic substitution ciphers?

Answer:

(decrypt to find out)

To enhance security, let us choose a key such as “PEACE” and put it into the grid, Figure 3:

Figure 3

I excluded the last “E” in “PEACE” because no letter should be written twice. Now let’s fill in the rest of the letters and have our personalized grid

Figure 4

Although we can change the grid every time we use a different keyword, this encryption scheme is not secure as it used to be at its time, because the use of symbols is no impediment to modern cryptanalysis techniques.

At the end of this article, here is a gift for you:

Right Click on Figure 5 and choose Save Target As to download a Masonic Cipher & Symbols Font for your MS Word, so you could write the symbols easily and have fun with your friends.

Figure 5: Masonic Cipher & Symbols Font (4)

To install the font file Right Click on it and select Install or simply move it to your C:\Windows\Fonts folder.

References:

[1] http://www.forgotten-ny.com/forgottentour17/tour17.html
[2] David Kahn, “The Codebreakers. The Story of Secret Writing.” Macmillan, 1967.
[3] David E. Newton, “Freemason’s Cipher” in Encyclopedia of Cryptology, 1998.
[4] FAM-Code© http://www.odr.org/anonymous/fam-code.htm

Haiders WebSpace » Symmetric Encryption

Applet implementation to code Caesar’s substitution cipher

The pigpen cipher aka Masonic cipher