PayPal\Security\Cipher::encrypt PHP Method

    public function encrypt($input)
    {
        // Create a random IV. Not using mcrypt to generate one, as to not have a dependency on it.
        $iv = substr(uniqid("", true), 0, Cipher::IV_SIZE);
        // Encrypt the data
        $encrypted = openssl_encrypt($input, "AES-256-CBC", $this->secretKey, 0, $iv);
        // Encode the data with IV as prefix
        return base64_encode($iv . $encrypted);
    }

 /**
  * Helper method to encrypt data using clientSecret as key
  *
  * @param $data
  * @return string
  */
 public function encrypt($data)
 {
     return $this->cipher->encrypt($data);
 }