During web development, sometimes you need to display some sensitive information to the client. Such as url, string. You can encrypt/decrypt String using AES 128 bits encryption algorithm.

Source Code

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.util.Base64;

/**
 * Program to Encrypt/Decrypt String Using AES 128 bit Encryption Algorithm
 */
public class EncryptDecryptString {

    private static final String encryptionKey = "ABCDEFGHIJKLMNOP";
    private static final String characterEncoding = "UTF-8";
    private static final String cipherTransformation = "AES/CBC/PKCS5PADDING";
    private static final String aesEncryptionAlgorithem = "AES";


    /**
     * Method for Encrypt Plain String Data
     *
     * @param plainText
     * @return encryptedText
     */
    public static String encrypt(String plainText) {
        String encryptedText = "";
        try {
            Cipher cipher = Cipher.getInstance(cipherTransformation);
            byte[] key = encryptionKey.getBytes(characterEncoding);
            SecretKeySpec secretKey = new SecretKeySpec(key, aesEncryptionAlgorithem);
            IvParameterSpec ivparameterspec = new IvParameterSpec(key);
            cipher.init(Cipher.ENCRYPT_MODE, secretKey, ivparameterspec);
            byte[] cipherText = cipher.doFinal(plainText.getBytes("UTF8"));
            Base64.Encoder encoder = Base64.getEncoder();
            encryptedText = encoder.encodeToString(cipherText);
        } catch (Exception E) {
            System.err.println("Encrypt Exception : " + E.getMessage());
        }
        return encryptedText;
    }

    /**
     * Method For Get encryptedText and Decrypted provided String
     *
     * @param encryptedText
     * @return decryptedText
     */
    public static String decrypt(String encryptedText) {
        String decryptedText = "";
        try {
            Cipher cipher = Cipher.getInstance(cipherTransformation);
            byte[] key = encryptionKey.getBytes(characterEncoding);
            SecretKeySpec secretKey = new SecretKeySpec(key, aesEncryptionAlgorithem);
            IvParameterSpec ivparameterspec = new IvParameterSpec(key);
            cipher.init(Cipher.DECRYPT_MODE, secretKey, ivparameterspec);
            Base64.Decoder decoder = Base64.getDecoder();
            byte[] cipherText = decoder.decode(encryptedText.getBytes("UTF8"));
            decryptedText = new String(cipher.doFinal(cipherText), "UTF-8");
        } catch (Exception E) {
            System.err.println("decrypt Exception : " + E.getMessage());
        }
        return decryptedText;
    }
}

Example

public class Test {
    public static void main(String[] args) {
        String plainString = "{\"hello\": \"world\"}";

        String encyptStr = EncryptDecryptString.encrypt(plainString);
        String decryptStr = EncryptDecryptString.decrypt(encyptStr);

        System.out.println("Plain   String  : " + plainString);
        System.out.println("Encrypt String  : " + encyptStr);
        System.out.println("Decrypt String  : " + decryptStr);
    }
}

Output

Plain   String  : {"hello": "world"}
Encrypt String  : YbhOplwpB8rq6J7euPmb6cZX+NMCWzKEvZ0tpF1K8NQ=
Decrypt String  : {"hello": "world"}