Areas of application for employees e.g. in logistics areas, parcel distribution stations, parcel delivery, or department stores.Replaces possible annoying test seals!In the aforementioned areas, the use of private cell phones is often not permitted, as it is difficult to clearly prove that a cell phone is being carried as property.A possibly stolen cell phone can be "personalized" very quickly and is then hardly recognizable as "stock or store goods".When installing or using the app, no device data such as IMEI or serial number or other data are read out.Rather, the app generates its own unique device number via the server, which is combined with an additional security code that is constantly changing. This creates a unique and unique "Identifier" code, which is displayed on your cell phone as a QR code.On the tester side, e.g. When entering the logistics area at the start of work, the "PrüferApp" (another independent app e.g. for the employer) can be used to scan and verify the ownership in a matter of seconds without having to read any personal data from your cell phone.The app works both with an internet connection and offline.