private function getSymmetricKeyLength($encType = CryptographyProviderInterface::PROPERTY_ENCRYPTION)
    {
        $cipherMethod = $this->getCipherMethod($encType);

        switch ($cipherMethod) {
            case 'AES-128-CBC':
                $length = 16;
                break;
            case 'AES-192-CBC':
                $length = 24;
                break;
            case 'AES-256-CBC':
                $length = 32;
                break;
            default:
                $length = 16;
                break;
        }

        return $length;
    }