Question

Java Programming

Part 1

File encryption is the science of writing the contents of a file in a secret code. Your encryption program should work like a filter, reading the contents of one file, modifying the data into a code, and then writing the coded contents out to a second file. The second file will be a version of the first file, but written in a secret code. Although there are complex encryption techniques, you should come up with a simple one of your own. For example, you could read the first file one character at a time, and add 10 to the character code of each character before it is written to the second file. I would like you to modify the program slightly. You should ask the user what the number is that is going to be used for the Encryption. Therefore the program will prompt the user for a number and apply it to the data in the file to create the encrypted file.

Part 2

File Decryption Filter
Write a program that decrypts the file produced by the program in Programming Challenge 7. The decryption program should read the contents of the coded file, restore the data to its original state, and write it to another file.

Note: Need this code simplified for a beginner class

Answer 1

2.

// ---------- Imported Packages ------------------
import java.text.*;
import java.util.*;
import javax.swing.*;
import java.awt.*;
import java.io.*;
import java.awt.event.*;
// -----------------------------------------------



class Problem12_8 extends PaintPanel
{
        JPanel topPanel = new JPanel();
        JPanel inputPanel = new JPanel(new GridLayout(2,1));
        JPanel outputPanel = new JPanel();
        JLabel inputLabel = new JLabel("File Name (*.dat):");
        JTextArea outputLabel = new JTextArea(25,25);
        JTextArea fileList = new JTextArea(25,25);
        final JTextField input = new JTextField(25);
        
        
        public Problem12_8()
        {
                buildPanel();
                
                add(KDUtil.fileHandleTest(topPanel));
                
                setVisible(true);
        }
        
        @Override
        public String getDescription()
        {
                return "8. File Decryption Filter"
+"\n\nWrite a program that decrypts the file produced by the program in Programming Challenge 7. The decryption program should read the contents of the coded file, "
+"\nrestore the data to its original state, and write it to another file.";
        }
        
        
        public void buildPanel()
        {
                /*input.addActionListener(new ActionListener() 
                {
                        public void actionPerformed(ActionEvent arg0) 
                        {
                                                if(input.getText().isEmpty()==false)
                                                {
                                                        outputLabel.setText("");
                                                        outputLabel.append(getFileWords(input.getText()));
                                                        outputLabel.setEditable(false);
                                                }                                                               
                        }
                });     */
                                        
                        
                JPanel mainPanel = new JPanel();
                mainPanel.setLayout(new BorderLayout());
                
                JLabel header = new JLabel("Decryption Program");
                JPanel headerFrame = new JPanel();
                headerFrame.add(header);
                mainPanel.add(headerFrame, BorderLayout.NORTH);
                

                
                JPanel wrapper = new JPanel();
                wrapper.add(inputLabel);
                wrapper.add(input);
                wrapper.add(new JLabel("Decryption Key"));
                final JTextField inputKey = new JTextField(10);
                wrapper.add(inputKey);
        
                inputPanel.add(wrapper);
                
                JButton create = new JButton("Read New File");
                create.addActionListener(new ActionListener() 
                {
                        public void actionPerformed(ActionEvent arg0) 
                        {
                                outputLabel.setText(" ");
                                populateList();
                                
                                String temp = "";
                                String key = inputKey.getText();

                                try
                                {

                                        RandomAccessFile output = new RandomAccessFile(input.getText(),"rw");
                                        boolean endOfFile = false;
                                        while(!endOfFile)
                                        {
                                                try
                                                {
                                                        temp = temp + output.readUTF();
                                                }
                                                catch(EOFException e)
                                                {
                                                        endOfFile = true;
                                                }
                                        }
                                        
                                }
                                catch(IOException e)
                                {
                                        outputLabel.append(e.getMessage());
                                }
                                
                                outputLabel.append(Decryption.decode(temp, key));
        
                        }
                });
                
                                
                
                wrapper = new JPanel();
                wrapper.add(create);
                
                inputPanel.add(wrapper);
                
                
                
                mainPanel.add(inputPanel, BorderLayout.CENTER);
                
        
                outputPanel.setLayout(new GridLayout(0,2));
                
                JPanel left = new JPanel(new BorderLayout());
                JPanel right = new JPanel(new BorderLayout());
                
                left.add(new JLabel("File List"), BorderLayout.NORTH);
                right.add(new JLabel("Decryption"), BorderLayout.NORTH);
                
                JScrollPane scrollFileList = new JScrollPane(fileList);
                left.add(scrollFileList, BorderLayout.CENTER);
                JScrollPane scroll = new JScrollPane(outputLabel);
                right.add(scroll, BorderLayout.CENTER);
                
                outputPanel.add(left);
                outputPanel.add(right);
                
                mainPanel.add(outputPanel, BorderLayout.SOUTH);

                populateList();
                topPanel.add(mainPanel);
                
        }
        
        private void populateList()
        {
                        try{
                                        String path = "."; 
                                        fileList.setText(" ");
 
                                        String files;
                                        File folder = new File(path);
                                        File[] listOfFiles = folder.listFiles(); 
 
                                        for (int i = 0; i < listOfFiles.length; i++) 
                                        {
 
                                           if (listOfFiles[i].isFile()) 
                                           {
                                                   files = listOfFiles[i].getName();
                                                        if(files.endsWith(".dat"))
                                                        fileList.append(files + "\n");
                                           }
                                   }
                        }
                        catch(java.security.AccessControlException k){}

        }

        
        
}                       

class Decryption
{
        public static String decode(String s, String key)
        {
                String temp = "";
                int coder = 0;
                
                for(int i = 0; i<key.length(); i++)
                {
                        coder = coder + (int)key.charAt(i);
                }
                
                for(int i = 0; i<s.length(); i++)
                {
                        int value = (int)s.charAt(i);
                        char k = (char)(value - coder);
                        
                        temp = temp + k;
                }
                
                return temp;
        }
}

1.

// ---------- Imported Packages ------------------
import java.text.*;
import java.util.*;
import javax.swing.*;
import java.awt.*;
import java.io.*;
import java.awt.event.*;
// -----------------------------------------------



class Problem12_7 extends PaintPanel
{
        JPanel topPanel = new JPanel();
        JPanel inputPanel = new JPanel(new GridLayout(2,1));
        JPanel outputPanel = new JPanel();
        JLabel inputLabel = new JLabel("File Name (*.dat):");
        JTextArea outputLabel = new JTextArea(25,25);
        JTextArea fileList = new JTextArea(25,25);
        final JTextField input = new JTextField(25);
        
        
        public Problem12_7()
        {
                try
                {
                try{RandomAccessFile test = new RandomAccessFile("test.txt","rw");test.close();}catch(IOException e){}

                buildPanel();
                }
                catch(java.security.AccessControlException k)
                {
                        topPanel.removeAll();
                        topPanel.add(new JLabel("ERROR: Applets cannot read or write files"));
                }       
                                
                                
                add(topPanel);
                setVisible(true);
        }
        
        @Override
        public String getDescription()
        {
                return "7. File Encryption Filter"
+"\n\nFile encryption is the science of writing the contents of a file in a secret code. Your encryption program should work like a filter, reading the contents of one file, "
+"\nmodifying the data into a code, and then writing the coded contents out to a second file. The second file will be a version of the first file, but written in a secret code."
+"\nAlthough there are complex encryption techniques, you should come up with a simple one of your own. For example, you could read the first file one character at a time, and add 10 to "
+"\nthe character code of each character before it is written to the second file.";
        }
        
        
        public void buildPanel()
        {
                /*input.addActionListener(new ActionListener() 
                {
                        public void actionPerformed(ActionEvent arg0) 
                        {
                                                if(input.getText().isEmpty()==false)
                                                {
                                                        outputLabel.setText("");
                                                        outputLabel.append(getFileWords(input.getText()));
                                                        outputLabel.setEditable(false);
                                                }                                                               
                        }
                });     */
                                        
                        
                JPanel mainPanel = new JPanel();
                mainPanel.setLayout(new BorderLayout());
                
                JLabel header = new JLabel("Encryption Program");
                JPanel headerFrame = new JPanel();
                headerFrame.add(header);
                mainPanel.add(headerFrame, BorderLayout.NORTH);
                

                
                JPanel wrapper = new JPanel();
                wrapper.add(inputLabel);
                wrapper.add(input);
                wrapper.add(new JLabel("Encryption Key"));
                final JTextField inputKey = new JTextField(10);
                wrapper.add(inputKey);
        
                inputPanel.add(wrapper);
                
                JButton create = new JButton("Write New File");
                create.addActionListener(new ActionListener() 
                {
                        public void actionPerformed(ActionEvent arg0) 
                        {
                                outputLabel.setText(" ");
                                String temp = fileList.getText();
                                String key = inputKey.getText();
                                
                                temp = Encryption.code(temp, key);
                                outputLabel.append(temp);       

                                try
                                {
                                        RandomAccessFile output = new RandomAccessFile(input.getText(),"rw");
                                        output.writeUTF(temp);
                                }
                                catch(IOException e)
                                {
                                        outputLabel.append(e.getMessage());
                                }
        
                        }
                });
                
                                
                
                wrapper = new JPanel();
                wrapper.add(create);
                
                inputPanel.add(wrapper);
                
                
                
                mainPanel.add(inputPanel, BorderLayout.CENTER);
                
        
                outputPanel.setLayout(new GridLayout(0,2));
                
                JPanel left = new JPanel(new BorderLayout());
                JPanel right = new JPanel(new BorderLayout());
                
                left.add(new JLabel("Input"), BorderLayout.NORTH);
                right.add(new JLabel("Encryption"), BorderLayout.NORTH);
                
                JScrollPane scrollFileList = new JScrollPane(fileList);
                left.add(scrollFileList, BorderLayout.CENTER);
                JScrollPane scroll = new JScrollPane(outputLabel);
                right.add(scroll, BorderLayout.CENTER);
                
                outputPanel.add(left);
                outputPanel.add(right);
                
                mainPanel.add(outputPanel, BorderLayout.SOUTH);

                topPanel.add(mainPanel);
        
        }
        
        
}                       

class Encryption
{
        public static String code(String s, String key)
        {
                String temp = "";
                int coder = 0;
                
                for(int i = 0; i<key.length(); i++)
                {
                        coder = coder + (int)key.charAt(i);
                }
                
                for(int i = 0; i<s.length(); i++)
                {
                        int value = (int)s.charAt(i);
                        char k = (char)(value + coder);
                        
                        temp = temp + k;
                }
                
                return temp;
        }
}