You are creating a user management system that will keep user profile and their credential or password. For security reason you’ll need to protect the password, to do this you can use the MessageDigest provided by Java API to encrypt the password. The code example below show you an example how to use it.

package org.kodejava.security;

import java.security.MessageDigest;

public class EncryptExample {
    public static void main(String[] args) {
        String password = "secret";
        String algorithm = "SHA";

        byte[] plainText = password.getBytes();

        try {
            MessageDigest digest = MessageDigest.getInstance(algorithm);
            digest.reset();
            digest.update(plainText);
            byte[] encodedPassword = digest.digest();

            StringBuilder builder = new StringBuilder();
            for (byte b : encodedPassword) {
                if ((b & 0xff) < 0x10) {
                    builder.append("0");
                }
                builder.append(Long.toString(b & 0xff, 16));
            }

            System.out.println("Plain    : " + password);
            System.out.println("Encrypted: " + builder.toString());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Here is the example of our encrypted password:

Plain    : secret
Encrypted: e5e9fa1ba31ecd1ae84f75caaa474f3a663f05f4