public function register()
{
    $this->app->singleton('encrypter', function ($app) {
        $config = $app->make('config')->get('app');

        // If the key starts with "base64:", we will need to decode the key before handing
        // it off to the encrypter. Keys may be base-64 encoded for presentation and we
        // want to make sure to convert them back to the raw bytes before encrypting.
        if (Str::startsWith($key = $this->key($config), 'base64:')) {
            $key = base64_decode(substr($key, 7));
        }

        return new Encrypter($key, $config['cipher']);
    });
}