protected function generateMasterToken()
    {
        return [
            hash('sha256', $this->tokenSalt.'+'.config('app.key').'+'.Carbon::now()->toDateString()),
            hash('sha256', $this->tokenSalt.'+'.config('app.key').'+'.Carbon::now()->addDay()->toDateString()),
            hash('sha256', $this->tokenSalt.'+'.config('app.key').'+'.Carbon::now()->subDay()->toDateString()),
        ];
    }