很多时候要对秘要进行持久化加密,此时的加密采用md5。采用对称加密的时候就采用DES方法了
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import java.io.IOException;
import java.security.MessageDigest;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import sun.misc.BASEDecoder;
import sun.misc.BASEEncoder;
/**
* 密匙工具类(包含des加密与md加密)
* @author mingge
*
*/
public class KeysUtil {
private final static String DES = "DES" ;
private final static String MD = "MD" ;
private final static String KEY= "opeddsaeaddadbcabf" ;
/**
* MD加密算法
* @param data
* @return
*/
public static String mdEncrypt(String data) {
String resultString = null ;
try {
resultString = new String(data);
MessageDigest md = MessageDigest.getInstance(MD);
resultString =bytehexString(md.digest(resultString.getBytes()));
} catch (Exception ex) {
}
return resultString;
}
private static String bytehexString( byte [] bytes) {
StringBuffer bf = new StringBuffer(bytes.length * );
for ( int i = ; i < bytes.length; i++) {
if ((bytes[i] & xff) < x) {
bf.append( "T" );
}
bf.append(Long.toString(bytes[i] & xff, ));
}
return bf.toString();
}
/**
* Description 根据键值进行加密
* @param data
* @param key 加密键byte数组
* @return
* @throws Exception
*/
public static String desEncrypt(String data, String key) throws Exception {
if (key== null ) {
key=KEY;
}
byte [] bt = encrypt(data.getBytes(), key.getBytes());
String strs = new BASEEncoder().encode(bt);
return strs;
}
/**
* Description 根据键值进行解密
* @param data
* @param key 加密键byte数组
* @return
* @throws IOException
* @throws Exception
*/
public static String desDecrypt(String data, String key) throws IOException,
Exception {
if (data == null ){
return null ;
}
if (key== null ) {
key=KEY;
}
BASEDecoder decoder = new BASEDecoder();
byte [] buf = decoder.decodeBuffer(data);
byte [] bt = decrypt(buf,key.getBytes());
return new String(bt);
}
/**
* Description 根据键值进行加密
* @param data
* @param key 加密键byte数组
* @return
* @throws Exception
*/
private static byte [] encrypt( byte [] data, byte [] key) throws Exception {
// 生成一个可信任的随机数源
SecureRandom sr = new SecureRandom();
// 从原始密钥数据创建DESKeySpec对象
DESKeySpec dks = new DESKeySpec(key);
// 创建一个密钥工厂,然后用它把DESKeySpec转换成SecretKey对象
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
SecretKey securekey = keyFactory.generateSecret(dks);
// Cipher对象实际完成加密操作
Cipher cipher = Cipher.getInstance(DES);
// 用密钥初始化Cipher对象
cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
return cipher.doFinal(data);
}
/**
* Description 根据键值进行解密
* @param data
* @param key 加密键byte数组
* @return
* @throws Exception
*/
private static byte [] decrypt( byte [] data, byte [] key) throws Exception {
// 生成一个可信任的随机数源
SecureRandom sr = new SecureRandom();
// 从原始密钥数据创建DESKeySpec对象
DESKeySpec dks = new DESKeySpec(key);
// 创建一个密钥工厂,然后用它把DESKeySpec转换成SecretKey对象
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
SecretKey securekey = keyFactory.generateSecret(dks);
// Cipher对象实际完成解密操作
Cipher cipher = Cipher.getInstance(DES);
// 用密钥初始化Cipher对象
cipher.init(Cipher.DECRYPT_MODE, securekey, sr);
return cipher.doFinal(data);
}
}
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下面在给大家介绍一段代码关于Java实现MD5加密解密类
Java实现MD5加密以及解密类,附带测试类,具体见代码。
MD5加密解密类——MyMD5Util,代码如下:
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package com.zyg.security.md5;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Arrays;
public class MyMD5Util {
private static final String HEX_NUMS_STR= "0123456789ABCDEF" ;
private static final Integer SALT_LENGTH = 12 ;
/**
* 将16进制字符串转换成字节数组
* @param hex
* @return
*/
public static byte [] hexStringToByte(String hex) {
int len = (hex.length() / 2 );
byte [] result = new byte [len];
char [] hexChars = hex.toCharArray();
for ( int i = 0 ; i < len; i++) {
int pos = i * 2 ;
result[i] = ( byte ) (HEX_NUMS_STR.indexOf(hexChars[pos]) << 4
| HEX_NUMS_STR.indexOf(hexChars[pos + 1 ]));
}
return result;
}
/**
* 将指定byte数组转换成16进制字符串
* @param b
* @return
*/
public static String byteToHexString( byte [] b) {
StringBuffer hexString = new StringBuffer();
for ( int i = 0 ; i < b.length; i++) {
String hex = Integer.toHexString(b[i] & 0xFF );
if (hex.length() == 1 ) {
hex = '0' + hex;
}
hexString.append(hex.toUpperCase());
}
return hexString.toString();
}
/**
* 验证口令是否合法
* @param password
* @param passwordInDb
* @return
* @throws NoSuchAlgorithmException
* @throws UnsupportedEncodingException
*/
public static boolean validPassword(String password, String passwordInDb)
throws NoSuchAlgorithmException, UnsupportedEncodingException {
//将16进制字符串格式口令转换成字节数组
byte [] pwdInDb = hexStringToByte(passwordInDb);
//声明盐变量
byte [] salt = new byte [SALT_LENGTH];
//将盐从数据库中保存的口令字节数组中提取出来
System.arraycopy(pwdInDb, 0 , salt, 0 , SALT_LENGTH);
//创建消息摘要对象
MessageDigest md = MessageDigest.getInstance( "MD5" );
//将盐数据传入消息摘要对象
md.update(salt);
//将口令的数据传给消息摘要对象
md.update(password.getBytes( "UTF-8" ));
//生成输入口令的消息摘要
byte [] digest = md.digest();
//声明一个保存数据库中口令消息摘要的变量
byte [] digestInDb = new byte [pwdInDb.length - SALT_LENGTH];
//取得数据库中口令的消息摘要
System.arraycopy(pwdInDb, SALT_LENGTH, digestInDb, 0 , digestInDb.length);
//比较根据输入口令生成的消息摘要和数据库中消息摘要是否相同
if (Arrays.equals(digest, digestInDb)) {
//口令正确返回口令匹配消息
return true ;
} else {
//口令不正确返回口令不匹配消息
return false ;
}
}
/**
* 获得加密后的16进制形式口令
* @param password
* @return
* @throws NoSuchAlgorithmException
* @throws UnsupportedEncodingException
*/
public static String getEncryptedPwd(String password)
throws NoSuchAlgorithmException, UnsupportedEncodingException {
//声明加密后的口令数组变量
byte [] pwd = null ;
//随机数生成器
SecureRandom random = new SecureRandom();
//声明盐数组变量
byte [] salt = new byte [SALT_LENGTH];
//将随机数放入盐变量中
random.nextBytes(salt);
//声明消息摘要对象
MessageDigest md = null ;
//创建消息摘要
md = MessageDigest.getInstance( "MD5" );
//将盐数据传入消息摘要对象
md.update(salt);
//将口令的数据传给消息摘要对象
md.update(password.getBytes( "UTF-8" ));
//获得消息摘要的字节数组
byte [] digest = md.digest();
//因为要在口令的字节数组中存放盐,所以加上盐的字节长度
pwd = new byte [digest.length + SALT_LENGTH];
//将盐的字节拷贝到生成的加密口令字节数组的前12个字节,以便在验证口令时取出盐
System.arraycopy(salt, 0 , pwd, 0 , SALT_LENGTH);
//将消息摘要拷贝到加密口令字节数组从第13个字节开始的字节
System.arraycopy(digest, 0 , pwd, SALT_LENGTH, digest.length);
//将字节数组格式加密后的口令转化为16进制字符串格式的口令
return byteToHexString(pwd);
}
}
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测试类——Client,代码如下:
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package com.zyg.security.md5;
import java.io.UnsupportedEncodingException;
import java.security.NoSuchAlgorithmException;
import java.util.HashMap;
import java.util.Map;
public class Client {
private static Map users = new HashMap();
public static void main(String[] args){
String userName = "zyg" ;
String password = "123" ;
registerUser(userName,password);
userName = "changong" ;
password = "456" ;
registerUser(userName,password);
String loginUserId = "zyg" ;
String pwd = "1232" ;
try {
if (loginValid(loginUserId,pwd)){
System.out.println( "欢迎登陆!!!" );
} else {
System.out.println( "口令错误,请重新输入!!!" );
}
} catch (NoSuchAlgorithmException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* 注册用户
*
* @param userName
* @param password
*/
public static void registerUser(String userName,String password){
String encryptedPwd = null ;
try {
encryptedPwd = MyMD5Util.getEncryptedPwd(password);
users.put(userName, encryptedPwd);
} catch (NoSuchAlgorithmException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* 验证登陆
*
* @param userName
* @param password
* @return
* @throws UnsupportedEncodingException
* @throws NoSuchAlgorithmException
*/
public static boolean loginValid(String userName,String password)
throws NoSuchAlgorithmException, UnsupportedEncodingException{
String pwdInDb = (String)users.get(userName);
if ( null !=pwdInDb){ // 该用户存在
return MyMD5Util.validPassword(password, pwdInDb);
} else {
System.out.println( "不存在该用户!!!" );
return false ;
}
}
}
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