Digital car keys, which let drivers lock, unlock and sometimes start a vehicle using a smartphone, are becoming increasingly common but carry risks alongside their convenience. As with any connected technology, users face potential issues such as a dead or lost phone, app malfunctions or server outages, though manufacturers have built in safeguards to address most of these scenarios. Understanding how the system works helps owners take sensible precautions.

The technology, available through Apple Wallet, Google Wallet and Samsung's own system, relies on standards set by the Car Connectivity Consortium since 2018 and uses ultra-wideband or near-field communication, which requires the phone to be physically close to the car, making it more resistant to the relay attacks that affect traditional key fobs. If a phone is stolen, extra authorisation layers and remote-lock features, such as Apple's automatic CarKey lockdown when a device is marked lost, help prevent unauthorised access. Even a dead battery is not usually a dealbreaker, as most digital keys retain enough reserve power via NFC to function for up to five hours afterwards. Experts still recommend keeping a physical key fob as a backup and ensuring phones stay charged and updated.