import java.security.MessageDigest;

import java.util.Random;

import com.sun.org.apache.xerces.internal.impl.dv.util.HexBin;

/**

* @fileName Md5PasswordUtil.java

* @Description 明文密码加密加盐操作

* 1：生成加密密码：首先使用randomSalt获取随机盐值，并保存;再将随机盐值和明文密码传入generate生成加密密文

* 2：密码校验：将明文密码和加密后的密文传入verify，校验成功返回true，反则返回false

* @author user

* @date 2017年9月6日

* @version 1.0

*/

public class Md5PasswordUtil {

/**

* 生成16位数的随机salt值

* @return

*/

public static String randomSalt(){

Random r = new Random();

StringBuilder sb = new StringBuilder(16);

sb.append(r.nextInt(99999999)).append(r.nextInt(99999999));

int len = sb.length();

if (len < 16) {

for (int i = 0; i < 16 - len; i++) {

sb.append("0");

}

}

String salt = sb.toString();

return salt;

}

/**

* 生成含有随机盐的密码

* @param password 明文密码

* @param salt 盐值

* @return

*/

public static String generate(String password,String salt) {

password = md5Hex(password + salt);

char[] cs = new char[48];

for (int i = 0; i < 48; i += 3) {

cs[i] = password.charAt(i / 3 * 2);

char c = salt.charAt(i / 3);

cs[i + 1] = c;

cs[i + 2] = password.charAt(i / 3 * 2 + 1);

}

return new String(cs);

}

/**

* 校验密码是否正确

* @param password 明文密码

* @param md5 加密加盐后的密码

* @return

*/

public static boolean verify(String password, String md5) {

char[] cs1 = new char[32];

char[] cs2 = new char[16];

for (int i = 0; i < 48; i += 3) {

cs1[i / 3 * 2] = md5.charAt(i);

cs1[i / 3 * 2 + 1] = md5.charAt(i + 2);

cs2[i / 3] = md5.charAt(i + 1);

}

String salt = new String(cs2);

return md5Hex(password + salt).equals(new String(cs1));

}

/**

* 获取十六进制字符串形式的MD5摘要

*/

public static String md5Hex(String src) {

try {

MessageDigest md5 = MessageDigest.getInstance("MD5");

byte[] bs = md5.digest(src.getBytes());

new HexBin();

return new String(HexBin.encode(bs));

} catch (Exception e) {

e.printStackTrace();

return null;

}

}

}