Phone as a Key (PaaK)
Phone as a Key (PaaK) describes a system in which a compatible smartphone carries the credential used to access or operate a vehicle.
Several user experiences fit the term
PaaK can require the user to tap the phone on an NFC reader, press a control in an app, or simply approach with the phone in a pocket. Hands-free systems commonly use Bluetooth Low Energy for discovery and authenticated communication and may add UWB for accurate distance measurement. NFC can provide a deliberate close-range alternative.
PaaK is not one universal technical standard. Manufacturer systems differ in device support, pairing, account requirements, offline behaviour, permission sharing, low-battery support, and whether the phone can start the vehicle as well as unlock it. A remote unlock command sent through the internet is also not necessarily a locally stored digital key.
Owners should configure the documented backup method, especially before travelling or changing phones. For how credentials, secure storage, NFC, BLE, and UWB work together, see Digital Keys.