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\t\tjava 对称加密实例 对文件加密

2014年07月16日 ⁄ 综合 ⁄ 共 8896字 ⁄ 字号 评论关闭

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 说明:文件加密 加密方法:三重DES加密
* 加密过程:对选中的文件加密后在同文件夹下生成一个增加了".tdes" 扩展名的加密文件
*
* 解密过程:对选中的加密文件(必须有".tdes"扩展名)进行解密
*/
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);
      System.out.println(bytOut.length+"@@@@@@@@@@@@@@@@@@");
      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;
}
}

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