code: public String encrypt(String data) {
  
          Objects.requireNonNull(data, "Data to be encrypted");
          
          if (!secretKeySpec.isPresent()) {
              return data;
          }
  
          try {
              // encrypt data
              Cipher cipher = Cipher.getInstance(ALGORITHM);
              cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec.get());
              byte[] encrypted = cipher.doFinal(data.getBytes(StandardCharsets.UTF_8));
  
              // convert encrypted bytes to string in base64
              return Base64.encodeBase64URLSafeString(encrypted);
  
          } catch (InvalidKeyException ex) {
              logger.error(getHelperLogMessage(), ex);
              throw new RuntimeException(ex);
          } catch (GeneralSecurityException ex) {
              logger.error("Failed to encrypt data.", ex);
              return "";
          }
      }
docs: Encrypts data with secret key.
  
  @param data text to encrypt
  @return encrypted text in base64 format