GoKawiilDigital car keys are not at risk for relay attacks like key fobs, whereby a thief amplifies the fob's signal to unlock the car without even having the fob in their possession. Instead, digital keys use ultra-wideband (UWB) or near-field communication (NFC) to communicate with your vehicle, so the car won't unlock unless your phone is actually nearby. But they aren't completely immune to attacks. If your phone is stolen and someone gets hold of it, this means they might be able to gain access to your vehicle. That said, most car makers include additional levels of authorization to help prevent thieves or even your underage kids from being able to access the car.
The best defense against this is to keep your phone as secure as possible with two-factor authentication, secure passwords and remote wiping capability in the event of loss or theft. There may also be an option to use a second device to suspend the digital key until you locate your phone. With iPhone, for example, all you need to do is mark your device as lost, and Apple CarKey will automatically lock down the app.
Another common concern is that scary scenario when your phone dies. It's bad enough not to be able to hail an Uber or call home, but what if this means you can't even get into your car? Thankfully, that isn't the case. Just as most key fobs have a hidden physical key or a secondary option to start your car if the battery dies, digital keys have failsafe options. With both Apple and Android, many keys and cards can work up to five hours after your device battery dies, using reserve power via NFC. There are concerns as well that Bluetooth or NFC technology might not be working, but it's unlikely. It's slightly more probable that the app could crash, freeze or require an update at the worst possible time. The company's cloud server could also go offline, though most big companies have backup servers just in case. None of these scenarios are common, but it's good to know what's possible.