JAVA文件加密器程序

import java.awt.*; 
import java.awt.event.*; 
import javax.swing.*; 
import java.io.*; 
import java.security.*; 

import javax.crypto.*; 
import javax.crypto.spec.*;
 
/** 
文件名：FileEncrypter.java 
JDK：1.40以上 

   *說明：文件加密 
加密方法：三重DES加密 

   *加密過程：
對選中的文件加密後在同文件夾下生成一個
   *增加了".tdes" 擴展名的加密文件
   *解密過程：對選中的加密文件（必須有".tdes"擴展名）進行解密 
   */
 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("文件選擇"); 
  c.add(fp); 
  final KeyPanel pp = new KeyPanel("密碼"); 
  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,"請選擇文件！","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,"請選擇文件！","提示",JOptionPane.OK_OPTION); 
   } 
  }); 
 } 
/** 
加密函數 
輸入： 
要加密的文件，密碼（由0-F組成，共48個字符，表示3個8位的密碼）如： 
AD67EA2F3BE6E5ADD368DFE03120B5DF92A8FD8FEC2F0746 
其中： 
AD67EA2F3BE6E5AD DES密碼一 
D368DFE03120B5DF DES密碼二 
92A8FD8FEC2F0746 DES密碼三 
輸出： 
對輸入的文件加密後，保存到同一文件夾下增加了".tdes"擴展名的文件中。 
*/ 
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,"密碼長度必須等於48！","錯誤信息",JOptionPane.ERROR_MESSAGE); 
  }catch(Exception e){ 
         e.printStackTrace(); 
   } 
 } 
/** 
解密函數 
輸入： 
要解密的文件，密碼（由0-F組成，共48個字符，表示3個8位的密碼）如： 
AD67EA2F3BE6E5ADD368DFE03120B5DF92A8FD8FEC2F0746 
其中： 
AD67EA2F3BE6E5AD DES密碼一 
D368DFE03120B5DF DES密碼二 
92A8FD8FEC2F0746 DES密碼三 
輸出： 
對輸入的文件解密後，保存到用戶指定的文件中。 
*/ 
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)); 
      //用戶指定要保存的文件 
      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,"密碼長度必須等於48！","錯誤信息",JOptionPane.ERROR_MESSAGE); 
  }catch(Exception e){ 
      JOptionPane.showMessageDialog(this,"解密失敗，請覈對密碼！","提示",JOptionPane.OK_OPTION); 
  } 
} 
/** 
用DES方法加密輸入的字節 
bytKey需爲8字節長，是加密的密碼 
*/ 
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方法解密輸入的字節 
bytKey需爲8字節長，是解密的密碼 
*/ 
 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); 
 } 
/** 
輸入密碼的字符形式，返回字節數組形式。 
如輸入字符串：AD67EA2F3BE6E5AD 
返回字節數組：{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; 
 } 
/** 
計算一個16進制字符的10進制值 
輸入：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; 
  } 
} 
/** 
文件選擇組件。 
*/ 
class FilePanel extends JPanel{ 
  FilePanel(String str){ 
   JLabel label = new JLabel(str); 
   JTextField fileText = new JTextField(35); 
   JButton chooseButton = new JButton("瀏覽..."); 
   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; 
 } 
} 
/** 
密碼生成組件。 
*/ 
class KeyPanel extends JPanel{ 
  KeyPanel(String str){ 
    JLabel label = new JLabel(str); 
    JTextField fileText = new JTextField(35); 
    JButton chooseButton = new JButton("隨機產生"); 
    this.add(label); 
    this.add(fileText); 
    this.add(chooseButton); 
    clickAction ca = new clickAction(this); 
    chooseButton.addActionListener(ca); 
} 
//返回生成的密碼（48個字符長度） 
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; 
 } 
}