三重DES加密程序

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import java.security.*;
import javax.crypto.*;
import javax.crypto.spec.*;
public class FileEncrypter extends JFrame{
 public static final int WIDTH = 550;
 public static final int HEIGHT = 200;
 public static void main(String args[]) {
   FileEncrypter fe = new FileEncrypter(); fe.show();
 }
FileEncrypter(){
  this.setSize(WIDTH,HEIGHT);
  this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  this.setResizable(false);
  Toolkit tk = Toolkit.getDefaultToolkit();
  Dimension screenSize = tk.getScreenSize();
  this.setLocation((screenSize.width - WIDTH)/2, (screenSize.height - HEIGHT)/2);
  this.setTitle("文件加密器(TriDES)");
  Container c = this.getContentPane();
  c.setLayout( new FlowLayout());
  final FilePanel fp = new FilePanel("文件选择");
  c.add(fp);
  final KeyPanel pp = new KeyPanel("密码");
  c.add(pp);
  JButton jbE = new JButton("加密");
  c.add(jbE);
  jbE.addActionListener(new ActionListener(){
  public void actionPerformed(ActionEvent event){
  File file = new File(fp.getFileName());
  if (file.exists())
    encrypt(file.getAbsoluteFile(),pp.getKey());
  else
    JOptionPane.showMessageDialog(
  null,"请选择文件！","提示",JOptionPane.OK_OPTION);
 }
 });
  JButton jbD = new JButton("解密");
  c.add(jbD);
  jbD.addActionListener(new ActionListener(){
    public void actionPerformed(ActionEvent event){
     File file = new File(fp.getFileName());
     if (file.exists())
      decrypt(file.getAbsoluteFile(),pp.getKey());
     else
      JOptionPane.showMessageDialog(null,"请选择文件！","提示",JOptionPane.OK_OPTION);
   }
  });
 }
/**
加密函数
输入：
要加密的文件，密码（由0-F组成，共48个字符，表示3个8位的密码）如：
AD67EA2F3BE6E5ADD368DFE03120B5DF92A8FD8FEC2F0746
其中：
AD67EA2F3BE6E5AD DES密码一
D368DFE03120B5DF DES密码二
92A8FD8FEC2F0746 DES密码三
输出：
对输入的文件加密后，保存到同一文件夹下增加了".tdes"扩展名的文件中。
*/
private void encrypt(File fileIn,String sKey){
  try{
   if(sKey.length() == 48){
     byte[] bytK1 = getKeyByStr(sKey.substring(0,16));
     byte[] bytK2 = getKeyByStr(sKey.substring(16,32));
     byte[] bytK3 = getKeyByStr(sKey.substring(32,48));
     FileInputStream fis = new FileInputStream(fileIn);
     byte[] bytIn = new byte[(int)fileIn.length()];
     for(int i = 0;i< fileIn.length();i++){
      bytIn[i] = (byte)fis.read();
     }
    //加密
    byte[] bytOut = encryptByDES(encryptByDES(encryptByDES(bytIn,bytK1),bytK2),bytK3);
    String fileOut = fileIn.getPath() + ".tdes";
    FileOutputStream fos = new FileOutputStream(fileOut);
    for(int i = 0;i< bytOut.length;i++){
      fos.write((int)bytOut[i]);
    }
    fos.close();
    JOptionPane.showMessageDialog(this,"加密成功！","提示",JOptionPane.OK_OPTION);
  }else
    JOptionPane.showMessageDialog(
    this,"密码长度必须等于48！","错误信息",JOptionPane.ERROR_MESSAGE);
  }catch(Exception e){
         e.printStackTrace();
   }
 }
/**
解密函数
输入：
要解密的文件，密码（由0-F组成，共48个址硎?个8位的密码）如：
AD67EA2F3BE6E5ADD368DFE03120B5DF92A8FD8FEC2F0746
其中：
AD67EA2F3BE6E5AD DES密码一
D368DFE03120B5DF DES密码二
92A8FD8FEC2F0746 DES密码三
输出：
对输入的文件解密后，保存到用户指定的文件中。
*/
private void decrypt(File fileIn,String sKey){
  try{
    if(sKey.length() == 48){
      String strPath = fileIn.getPath();
      if(strPath.substring(strPath.length()-5).toLowerCase().equals(".tdes"))
        strPath = strPath.substring(0,strPath.length()-5);
      else{
        JOptionPane.showMessageDialog(this,"不是合法的加密文件！","提示",JOptionPane.OK_OPTION);
        return;
      }
      JFileChooser chooser = new JFileChooser();
      chooser.setCurrentDirectory(new File("."));
      chooser.setSelectedFile(new File(strPath));
      //用户指定要保存的文件
      int ret = chooser.showSaveDialog(this);
      if(ret==JFileChooser.APPROVE_OPTION){
        byte[] bytK1 = getKeyByStr(sKey.substring(0,16));
        byte[] bytK2 = getKeyByStr(sKey.substring(16,32));
        byte[] bytK3 = getKeyByStr(sKey.substring(32,48));
 
        FileInputStream fis = new FileInputStream(fileIn);
        byte[] bytIn = new byte[(int)fileIn.length()];
        for(int i = 0;i< fileIn.length();i++){
            bytIn[i] = (byte)fis.read();
        }
     //解密
     byte[] bytOut = decryptByDES(decryptByDES(decryptByDES(bytIn,bytK3),bytK2),bytK1);
     File fileOut = chooser.getSelectedFile();
     fileOut.createNewFile();
     FileOutputStream fos = new FileOutputStream(fileOut);
     for(int i = 0;i< bytOut.length;i++){
          fos.write((int)bytOut[i]);
      }
     fos.close();
     JOptionPane.showMessageDialog(this,"解密成功！","提示",JOptionPane.OK_OPTION);
    }
   }else
      JOptionPane.showMessageDialog(this,"密码长度必须等于48！","错误信息",JOptionPane.ERROR_MESSAGE);
  }catch(Exception e){
      JOptionPane.showMessageDialog(this,"解密失败，请核对密码！","提示",JOptionPane.OK_OPTION);
  }
}
/**
用DES方法加密输入的字节
bytKey需为8字节长，是加密的密码
*/
private byte[] encryptByDES(byte[] bytP,byte[] bytKey) throws Exception{
   DESKeySpec desKS = new DESKeySpec(bytKey);
   SecretKeyFactory skf = SecretKeyFactory.getInstance("DES");
   SecretKey sk = skf.generateSecret(desKS);
   Cipher cip = Cipher.getInstance("DES");
   cip.init(Cipher.ENCRYPT_MODE,sk);
   return cip.doFinal(bytP);
}
/**
用DES方法解密输入的字节
bytKey需为8字节长，是解密的密码
*/
 private byte[] decryptByDES(byte[] bytE,byte[] bytKey) throws Exception{
   DESKeySpec desKS = new DESKeySpec(bytKey);
   SecretKeyFactory skf = SecretKeyFactory.getInstance("DES");
   SecretKey sk = skf.generateSecret(desKS);
   Cipher cip = Cipher.getInstance("DES");
   cip.init(Cipher.DECRYPT_MODE,sk);
    return cip.doFinal(bytE);
 }
/**
输入密码的字符形式，返回字节数组形式。
如输入字符串：AD67EA2F3BE6E5AD
返回字节数组：{173,103,234,47,59,230,229,173}
*/
private byte[] getKeyByStr(String str){
   byte[] bRet = new byte[str.length()/2];
   for(int i=0;i< str.length()/2;i++){
     Integer itg =new Integer(16*getChrInt(str.charAt(2*i)) + getChrInt(str.charAt(2*i+1)));
     bRet[i] = itg.byteValue();
   }
    return bRet;
 }
/**
计算一个16进制字符的10进制值
输入：0-F
*/
private int getChrInt(char chr){
  int iRet=0;
  if(chr=="0".charAt(0)) iRet = 0;
  if(chr=="1".charAt(0)) iRet = 1;
  if(chr=="2".charAt(0)) iRet = 2;
  if(chr=="3".charAt(0)) iRet = 3;
  if(chr=="4".charAt(0)) iRet = 4;
  if(chr=="5".charAt(0)) iRet = 5;
  if(chr=="6".charAt(0)) iRet = 6;
  if(chr=="7".charAt(0)) iRet = 7;
  if(chr=="8".charAt(0)) iRet = 8;
  if(chr=="9".charAt(0)) iRet = 9;
  if(chr=="A".charAt(0)) iRet = 10;
  if(chr=="B".charAt(0)) iRet = 11;
  if(chr=="C".charAt(0)) iRet = 12;
  if(chr=="D".charAt(0)) iRet = 13;
  if(chr=="E".charAt(0)) iRet = 14;
  if(chr=="F".charAt(0)) iRet = 15;
    return iRet;
  }
}
/**
文件选择组件。
*/
class FilePanel extends JPanel{
  FilePanel(String str){
   JLabel label = new JLabel(str);
   JTextField fileText = new JTextField(35);
   JButton chooseButton = new JButton("浏览...");
   this.add(label);
   this.add(fileText);
   this.add(chooseButton);
   clickAction ca = new clickAction(this);
   chooseButton.addActionListener(ca);
}
public String getFileName(){
JTextField jtf = (JTextField)this.getComponent(1);
return jtf.getText();
}
private class clickAction implements ActionListener{
  clickAction(Component c){
   cmpt = c;
  }
  public void actionPerformed(ActionEvent event){
    JFileChooser chooser = new JFileChooser();
    chooser.setCurrentDirectory(new File("."));
    int ret = chooser.showOpenDialog(cmpt);
    if(ret==JFileChooser.APPROVE_OPTION){
       JPanel jp = (JPanel)cmpt;
       JTextField jtf = (JTextField)jp.getComponent(1);
       jtf.setText(chooser.getSelectedFile().getPath());
     }
  }
  private Component cmpt;
 }
}
/**
密码生成组件。
*/
class KeyPanel extends JPanel{
  KeyPanel(String str){
    JLabel label = new JLabel(str);
    JTextField fileText = new JTextField(35);
    JButton chooseButton = new JButton("随机产生");
    this.add(label);
    this.add(fileText);
    this.add(chooseButton);
    clickAction ca = new clickAction(this);
    chooseButton.addActionListener(ca);
}
//返回生成的密码（48个字符长度）
public String getKey(){
  JTextField jtf = (JTextField)this.getComponent(1);
  return jtf.getText();
}
private class clickAction implements ActionListener{
  clickAction(Component c){
   cmpt = c;
  }
public void actionPerformed(ActionEvent event){
 try{
   KeyGenerator kg = KeyGenerator.getInstance("DES");
   kg.init(56);
   Key ke = kg.generateKey();
   byte[] bytK1 = ke.getEncoded();
   ke = kg.generateKey();
   byte[] bytK2 = ke.getEncoded();
   ke = kg.generateKey();
   byte[] bytK3 = ke.getEncoded();
   JPanel jp = (JPanel)cmpt;
   JTextField jtf = (JTextField)jp.getComponent(1);
   jtf.setText(getByteStr(bytK1)+getByteStr(bytK2)+getByteStr(bytK3));
 }catch(Exception e){
    e.printStackTrace();
  }
}
private String getByteStr(byte[] byt){
  String strRet = "";
  for(int i=0;i< byt.length;i++){
   //System.out.println(byt[i]);
   strRet += getHexValue((byt[i]&240)/16);
   strRet += getHexValue(byt[i]&15);
  }
  return strRet;
}
private String getHexValue(int s){
   String sRet=null;
   switch (s){
    case 0: sRet = "0";break;
    case 1: sRet = "1";break;
    case 2: sRet = "2";break;
    case 3: sRet = "3";break;
    case 4: sRet = "4";break;
    case 5: sRet = "5";break;
    case 6: sRet = "6";break;
    case 7: sRet = "7";break;
    case 8: sRet = "8";break;
    case 9: sRet = "9";break;
    case 10: sRet = "A";break;
    case 11: sRet = "B";break;
    case 12: sRet = "C";break;
    case 13: sRet = "D";break;
    case 14: sRet = "E";break;
    case 15: sRet = "F";
 }
   return sRet;
}
  private Component cmpt;
 }
}