文件加密或者解密.txt

语言采用java语言开发 采用des加密技术

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：  
	AD67EA2F3BE6E5AD D368DFE03120B5DF 92A8FD8FEC2F0746  
	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);  
	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;  
	}  
	}