[MD5] quickly realize MD5 encryption and decryption (salt value)

scene : Simulate user account registration, password encryption and login verification

Here is a customized user class that owns username and password Field , As a reference

1. User password encryption storage

// Simulate the user name and password at the time of user registration 
String username = "username";
String password = "123456";

// obtain User object 
User user = new User();

// Get salt value   
String salt = CodecUtils.generateSalt();

// Encrypt the password through the salt value 
password = CodecUtils.md5Hex(password, salt);

// Store the encrypted password and salt value into the object 
user.setSalt(salt);
user.setPassword(password);
user.setUsername(username);

// Final data warehousing 

2. Perform password decryption verification when the user logs in

// Simulate the user name and password entered when the user logs in 
String pw = "123456";
String username = "username";

// Get the user information through the user name 
User user = UserMapper.findByUserName(username);

// Judge user Is it empty   If it is blank, return null
if (user == null) {
    return null;
}

// Get the user Salt value in object 
String salt = user.getSalt();

// Get the user Password in object 
String password= user.getPassword();

// Decrypt the password through the tool class 
password = CodecUtils.md5Hex(password, salt);

if(password.equals(pw)){
    System.out.println(" Login successful ");
}else{
    System.out.println(" Login failed ");
}

3. The last attached MD5 Tool class

public class CodecUtils {

    public static String md5Hex(String data,String salt) {
        if (StringUtils.isBlank(salt)) {
            salt = data.hashCode() + "";
        }
        return DigestUtils.md5Hex(salt + DigestUtils.md5Hex(data));
    }

    public static String shaHex(String data, String salt) {
        if (StringUtils.isBlank(salt)) {
            salt = data.hashCode() + "";
        }
        return DigestUtils.sha512Hex(salt + DigestUtils.sha512Hex(data));
    }

    public static String generateSalt(){
        return StringUtils.replace(UUID.randomUUID().toString(), "-", "");
    }
}