Encryption.java

import java.nio.charset.StandardCharsets;
import java.security.AlgorithmParameters;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Base64;
public class Encryption {
    public String encrypt(String word, String password) throws Exception {
        byte[] ivBytes;
        
        SecureRandom random = new SecureRandom();
        byte[] bytes = new byte[20];
        random.nextBytes(bytes);
        byte[] saltBytes = bytes;

        // Derive the key
        SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
        PBEKeySpec spec = new PBEKeySpec(password.toCharArray(), saltBytes, 1500, 256);
        SecretKey secretKey = factory.generateSecret(spec);
        SecretKeySpec secret = new SecretKeySpec(secretKey.getEncoded(), "AES");

        //encrypting the word
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, secret);
        AlgorithmParameters params = cipher.getParameters();
        ivBytes = params.getParameterSpec(IvParameterSpec.class).getIV();
        byte[] encryptedTextBytes = cipher.doFinal(word.getBytes(StandardCharsets.UTF_8));
        //prepend salt and vi
        byte[] buffer = new byte[saltBytes.length + ivBytes.length + encryptedTextBytes.length];
        System.arraycopy(saltBytes, 0, buffer, 0, saltBytes.length);
        System.arraycopy(ivBytes, 0, buffer, saltBytes.length, ivBytes.length);
        System.arraycopy(encryptedTextBytes, 0, buffer, saltBytes.length + ivBytes.length, encryptedTextBytes.length);
        return new Base64().encodeToString(buffer);
    }
}