fileencrypter.java

java 实现对3DES 的加密.

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); 
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; 
} 
}