Apple details how UWB digital car keys will work in iOS 15

Apple UWB digital car keys diagram
DIGITAL KEY: The shared ranging key is used to start a secure-ranging session with the car’s UWB transceivers so it can track the location and trajectory of the iPhone or Apple Watch

Apple has revealed further details of how its new digital car keys for iOS 15 will use both ultra wideband (UWB) and Bluetooth Low Energy (BLE) technology to let motorists lock, unlock and start their vehicle without having to take their iPhone out of their bag or pocket.

The company announced its UWB-based digital car key feature in January and confirmed that it is adding a wider range of digital key and digital ID options to iOS 15 and to watchOS 8 for Apple Watch users earlier this month.

Apple has now released a video of a session held at its Worldwide Developers Conference (WWDC21) at the start of June that explains how its digital car keys will use UWB and BLE technology via a device’s U1 chip and secure element (SE) to generate “session-specific UWB ranging keys” and enable a range of “passive entry” functions.

How it works

“Cars are equipped with multiple UWB and BLE transceivers to ensure 360-degree coverage,” the video says.

“When the user first approaches the car, your iPhone or Apple Watch is detected using BLE. Upon proximity detection, a communication channel with the car is established.

“Upon connection, the car authenticates the device and a shared ranging key is derived on both sides.

“This operation takes place inside the secure element and generates a key that is unique to each session. The derived key is used to start a secure-ranging session with UWB transceivers, which allows the car to localise the device and map its trajectory.

“The car continues to map the trajectory of the device as the user approaches the car.

“Based on the location and trajectory of the device, the car can decide to trigger welcome features, such as turning on lights or adjusting seats.

“And when the device is localised inside the unlock zone, the car can initiate unlock operations before the user touches the door handle.

“With precise knowledge of whether the user’s device is inside or outside the car, the engine only starts when a device with a valid key is detected inside the car.”

Apple’s iOS 15 preview does not indicate whether the other digital keys — including home, workplace and hotel room — that it is adding to the system update will also be UWB-enabled.

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