MD5随机盐值生成法

public class Test3 {

/**
* 生成含有随机盐的密码
*/
public static String generate(String password) {
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();
password = md5Hex(password + salt);
char[] cs = new char[48];
for (int i = 0; i < 48; i += 3) {
//取MD5后密文的第一位
cs[i] = password.charAt(i / 3 * 2);

//取盐值的第一位
char c = salt.charAt(i / 3);
cs[i + 1] = c;

//取MD5后密文的第二位
cs[i + 2] = password.charAt(i / 3 * 2 + 1);
}

//生成的密文包括MD5的密文和盐值，顺序为一位密文，一位盐值，一位密文
return new String(cs);
} 

/**
* 校验密码是否正确
*/
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());
return new String(new Hex().encode(bs));
} catch (Exception e) {
return null;
}
} 

public static void main(String[] args) {
String password = generate("admin");
System.out.println(password);
System.out.println(verify("admin", password));
}