Phone-as-a-Key is a technology in which the smartphone
takes over the function of a radio key. This technology is used to open cars, but can also be used for normal door locks. Phone-as-a-Key is a radio-based technology. It works with Bluetooth Low Energy (BLE) and is used in automotive technology in Passive Entry Passive Start (PEPS), among others, and checks the authentication with the transmitted random number and verifies the digital signature. Bluetooth Low Energy is predestined for use in Phone-as-a-Service because of its low power requirements and the possibility of determining the direction from which the radio signals are coming.