用java写个文件加密的代码该怎么写

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 = 0i<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 = 0i<BYTOUT.LENGTHI++){

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 = 0i<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 = 0i<BYTOUT.LENGTHI++){

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=0i<STR.LENGTH()

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=0i<BYT.LENGTHI++){

//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

}

}

import java.util.Scanner

public class Test {

public static final int KEY = 8

public static void main(String[] args) {

String str = "十点进攻"

StringBuffer str2 = new StringBuffer() //存储加密后的字符串

StringBuffer str3 = new StringBuffer() //存储解密后的字符串

//加密过程

for(int i=0i<str.length()i++)

{

char c = (char)(str.charAt(i) ^ KEY)

str2.append(c)

}

//解密过程

for(int i=0i<str2.length()i++)

{

char c = (char)(str2.charAt(i) ^ KEY)

str3.append(c)

}

System.out.println("原始 的字符串为:" + str)

System.out.println("加密后 的字符串为:" + str2)

System.out.println("解密后 的字符串为:" + str3)

}

}

md5加密：

package com.ncs.pki.util

import java.security.MessageDigest

import java.security.NoSuchAlgorithmException

public class MD5Test {

private static MessageDigest digest = null

public synchronized static final String hash(String data) {

if (digest == null) {

try {

digest = MessageDigest.getInstance("MD5")

} catch (NoSuchAlgorithmException nsae) {

System.err.println(

"Failed to load the MD5 MessageDigest. "

+ "Jive will be unable to function normally.")

nsae.printStackTrace()

}

}

// Now, compute hash.

digest.update(data.getBytes())

return encodeHex(digest.digest())

}

public static final String encodeHex(byte[] bytes) {

StringBuffer buf = new StringBuffer(bytes.length * 2)

int i

for (i = 0i <bytes.lengthi++) {

if (((int) bytes[i] &0xff) <0x10) {

buf.append("0")

}

buf.append(Long.toString((int) bytes[i] &0xff, 16))

}

return buf.toString()

}

public static String test(){

return null

}

/**

* @param args

*/

public static void main(String[] args) {

// TODO Auto-generated method stub

System.out.println(MD5Test.hash("123456"))

}

}

3des加密：

package com.ncs.pki.util

import java.security.Key

import java.security.SecureRandom

import javax.crypto.Cipher

import javax.crypto.KeyGenerator

import sun.misc.BASE64Decoder

import sun.misc.BASE64Encoder

public class DesEncrypt {

/**

*

* 使用DES加密与解密,可对byte[],String类型进行加密与解密 密文可使用String,byte[]存储.

*

* 方法: void getKey(String strKey)从strKey的字条生成一个Key

*

* String getEncString(String strMing)对strMing进行加密,返回String密文 String

* getDesString(String strMi)对strMin进行解密,返回String明文

*

*byte[] getEncCode(byte[] byteS)byte[]型的加密 byte[] getDesCode(byte[]

* byteD)byte[]型的解密

*/

Key key

/**

* 根据参数生成KEY

*

* @param strKey

*/

public void getKey(String strKey) {

try {

KeyGenerator _generator = KeyGenerator.getInstance("DES")

_generator.init(new SecureRandom(strKey.getBytes()))

this.key = _generator.generateKey()

_generator = null

} catch (Exception e) {

e.printStackTrace()

}

}

/**

* 加密String明文输入,String密文输出

*

* @param strMing

* @return

*/

public String getEncString(String strMing) {

byte[] byteMi = null

byte[] byteMing = null

String strMi = ""

BASE64Encoder base64en = new BASE64Encoder()

try {

byteMing = strMing.getBytes("UTF8")

byteMi = this.getEncCode(byteMing)

strMi = base64en.encode(byteMi)

} catch (Exception e) {

e.printStackTrace()

} finally {

base64en = null

byteMing = null

byteMi = null

}

return strMi

}

/**

* 解密 以String密文输入,String明文输出

*

* @param strMi

* @return

*/

public String getDesString(String strMi) {

BASE64Decoder base64De = new BASE64Decoder()

byte[] byteMing = null

byte[] byteMi = null

String strMing = ""

try {

byteMi = base64De.decodeBuffer(strMi)

byteMing = this.getDesCode(byteMi)

strMing = new String(byteMing, "UTF8")

} catch (Exception e) {

e.printStackTrace()

} finally {

base64De = null

byteMing = null

byteMi = null

}

return strMing

}

/**

* 加密以byte[]明文输入,byte[]密文输出

*

* @param byteS

* @return

*/

private byte[] getEncCode(byte[] byteS) {

byte[] byteFina = null

Cipher cipher

try {

cipher = Cipher.getInstance("DES")

cipher.init(Cipher.ENCRYPT_MODE, key)

byteFina = cipher.doFinal(byteS)

} catch (Exception e) {

e.printStackTrace()

} finally {

cipher = null

}

return byteFina

}

/**

* 解密以byte[]密文输入,以byte[]明文输出

*

* @param byteD

* @return

*/

private byte[] getDesCode(byte[] byteD) {

Cipher cipher

byte[] byteFina = null

try {

cipher = Cipher.getInstance("DES")

cipher.init(Cipher.DECRYPT_MODE, key)

byteFina = cipher.doFinal(byteD)

} catch (Exception e) {

e.printStackTrace()

} finally {

cipher = null

}

return byteFina

}

public static void main(String[] args) {

System.out.println("des demo")

DesEncrypt des = new DesEncrypt()// 实例化一个对像

des.getKey("MYKEY")// 生成密匙

System.out.println("key=MYKEY")

String strEnc = des.getEncString("111111")// 加密字符串,返回String的密文

System.out.println("密文=" + strEnc)

String strDes = des.getDesString(strEnc)// 把String 类型的密文解密

System.out.println("明文=" + strDes)

}

}

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