Java实现三重DES加密算法
信息安全原理课，本以为会学刺激的攻防，各种注入渗透，然而事实上学的是加密解密。下面代码是抄书的一个实验。
本着学习DES算法的心态我手敲了一遍，然而完全就是写界面，核心算法用的是包里的。。
anyway，既然代码已经敲出来了就贴一下吧，java 写的一个桌面版程序，虽然丑了点，但也不是太难写。
代码很冗余，写这段代码的人程序能力肯定不行，但是我也没去改啦：
import java.awt.*;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.DESedeKeySpec;
import javax.swing.*;
import java.awt.event.*;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
public class FileEncrypter extends JFrame{
public static void main(String[] args) {
FileEncrypter fe = new FileEncrypter();
fe.show();
}
FileEncrypter(){
this.setSize(550,200);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocation(400,300);
this.setTitle("吟游诗人--3DES加密工具");
Container c = this.getContentPane();
c.setLayout(new FlowLayout());
JLabel label = new JLabel("选择文件");
c.add(label);
final JTextField fileText = new JTextField(35);
c.add(fileText);
JButton chooseButton = new JButton("浏览");
chooseButton.addActionListener(new ActionListener(){
//浏览按钮的点击事件监听
@Override
public void actionPerformed(ActionEvent e){
JFileChooser chooser = new JFileChooser();
chooser.setCurrentDirectory(new File("."));
int result = chooser.showOpenDialog(null);
if(result == JFileChooser.APPROVE_OPTION){
//获得文件绝对路径
String path = chooser.getSelectedFile().getAbsolutePath();
fileText.setText(path);
}
}
});
c.add(chooseButton);
JLabel label2 = new JLabel("秘钥(24个字符):");
c.add(label2);
final JTextField keyText = new JTextField(35);
c.add(keyText);
JButton jbe = new JButton("加密");
c.add(jbe);
jbe.addActionListener(new ActionListener(){
//以下编写"加密"按钮的监听和事件
@Override
public void actionPerformed(ActionEvent event) {
String wenjian,miyao;
wenjian = fileText.getText();
miyao = keyText.getText();
if("".equals(wenjian) || wenjian == null){
JOptionPane.showMessageDialog(null,"请选择文件！","提示",JOptionPane.OK_OPTION);
}else{
if("".equals(miyao) || miyao == null){
JOptionPane.showMessageDialog(null,"请输入24字节秘钥！","提示",JOptionPane.OK_OPTION);
}else{
if(miyao.length() != 24){
JOptionPane.showMessageDialog(null, "秘钥必须为24字节！","提示",JOptionPane.OK_OPTION);
}else{
//将三个秘钥分别 存入三个字节型数组中
byte[] key1 = miyao.substring(0,8).getBytes();
byte[] key2 = miyao.substring(8,16).getBytes();
byte[] key3 = miyao.substring(16,24).getBytes();
File file = new File(wenjian);
//读取明文并存入字节型数组plain中
byte[] plain = bytefromfile(file);
try {
byte[] bytOut = encryptByDES(encryptByDES(encryptByDES(plain,key1),key2),key3);
String fileOut = wenjian + ".tdes";
FileOutputStream fos = new FileOutputStream(fileOut);
for(int i = 0; i < bytOut.length; i++){
fos.write((int)bytOut[i]);
}
fos.close();
JOptionPane.showMessageDialog(null,"加密成功!","提示",JOptionPane.INFORMATION_MESSAGE);
} catch (Exception e) {
//e.printStackTrace();
JOptionPane.showMessageDialog(null,"加密失败!请检查文件或者秘钥","提示",JOptionPane.OK_OPTION);
}
}
}
}
}
});
JButton jbD = new JButton("解密");
c.add(jbD);
//解密按钮点击事件
jbD.addActionListener(new ActionListener(){
@Override
public void actionPerformed(ActionEvent arg0) {
String wenjian,wenjian1,miyao;
wenjian = fileText.getText();
miyao = keyText.getText();
if("".equals(wenjian) || wenjian == null){
JOptionPane.showMessageDialog(null,"请选择文件！","提示",JOptionPane.OK_OPTION);
return;
}
if(wenjian.substring(wenjian.length() - 5).toLowerCase().equals(".tdes")){
if(miyao.length()!=24){
JOptionPane.showMessageDialog(null, "秘钥必须为24字节！","提示",JOptionPane.OK_OPTION);
return;
}else{
wenjian1 = wenjian.substring(0,wenjian.length() - 5);
JFileChooser chooser = new JFileChooser();
chooser.setCurrentDirectory(new File("."));
//用户指定要保存的文件的位置
chooser.setSelectedFile(new File(wenjian1));
int ret = chooser.showSaveDialog(null);
if(ret == 0){
byte[] key1 = miyao.substring(0,8).getBytes();
byte[] key2 = miyao.substring(8,16).getBytes();
byte[] key3 = miyao.substring(16,24).getBytes();
File file = new File(wenjian);
//读取密文
byte[] miwen = bytefromfile(file);
try{
//解密
byte[] bytOut = decryptByDES(decryptByDES(decryptByDES(miwen,key3),key2),key1);
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(null, "解密成功！","提示",JOptionPane.INFORMATION_MESSAGE);
}catch (Exception e) {
JOptionPane.showMessageDialog(null, "解密失败！请检查文件或秘钥","提示",JOptionPane.OK_OPTION);
}
}
}
}else{
JOptionPane.showMessageDialog(null, "不是合法的加密文件！","提示",JOptionPane.OK_OPTION);
}
}
});
}
//从输入的文件中读取字节，保存于TextofFile数组中，并返回
private byte[] bytefromfile(File filein){
byte[] TextofFile = new byte[(int)filein.length()];
try{
FileInputStream fin = new FileInputStream(filein);
for(int i = 0; i < filein.length(); i++){
TextofFile[i] = (byte)fin.read();
}
fin.close();
}catch(IOException e){
e.printStackTrace();
}
return TextofFile;
}
//根据输入的明文进行加密
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);
}
//根据密文和秘钥进行解密
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);
}
}
运行截图：
