How digital keys stay safe if your phone is stolen

Even when a smartphone’s screen is locked, it can still unlock and start the car when using Digital Key 3.0, Phone-as-Key (BLE), or newer Digital Key (NFC). The phone can stay in your pocket and the car will still unlock and start (NFC versions require a tap). That might sound risky, but it isn’t: the car-key function on the phone only works when the phone is in its normal, owner-authorised state — the secure state the phone remains in during everyday use. If the phone is snatched, that state disappears very quickly.

When a thief grabs the phone, built-in protections activate and the car key function shuts down if the phone detects sudden movement or twisting associated with a grab, unusual handling patterns that resemble pickpocketing or mugging, or a swipe/touch/button press that isn’t followed by a correct Face ID, fingerprint or PIN attempt — along with other “something’s wrong” signals that indicate likely theft. These signals vary slightly by device model. In almost all real-world snatches, at least one of these triggers fires instantly, and the phone rapidly disables the digital-key function and stops acting as a car key.

If a thief snatches your phone at a moment when the screen happens to be unlocked while you were actively using it, the phone will shut down the car-key function as soon as the thief presses any button, the screen times out, a Face ID / Fingerprint / PIN attempt fails, or the phone detects sudden snatch-like movement. This gives the thief only a very narrow window to unlock and start the car, and it is extremely rare for cars to be stolen this way.

Digital keys (Phone-as-Key (BLE), Digital Key 3.0, Digital Key (NFC)) are stored inside a special secure chip on the phone (Apple’s Secure Enclave or Android’s StrongBox). It is this secure chip that enables — or shuts down — the car key function. Even if a thief knows your phone’s PIN, they still cannot copy, extract or transfer your digital car key, because it is physically protected against tampering and never releases the actual key data.

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