locking, unlocking, starting a car, sharing a car key without an actually sharing physical key is a reality now
CarKey "keys" live in the Wallet app and as we found in the first beta, can be shared with other people so you can allow others temporary access to your car. In the second beta of iOS 13.4, there's updated wording concerning sharing, which makes it clear that digital car keys will be able to be sent to people using the Messages app.
CarKey keys will be able to be shared with people in individual conversations but not in group conversations.
Sharing a CarKey with someone will allow that person to use their iPhone or Apple Watch to access a compatible car by holding the device near an NFC reader located inside of the vehicle. Keys can be permanent (for a spouse) or temporary (for a valet driver or mechanic).
People who receive a digital key over the Messages app will see text letting them know how it works.
[Vehicle Owner] invited you to use their car with unlocking & drive access. This allows you to use your iPhone and Apple Watch to unlock/lock the car, start the engine and drive.
CarKey access, like Apple Pay and Apple Cash, is authenticated biometrically using Face ID or Touch ID to make sure the person holding the iPhone is the person with permission to access a car, though there is an "Express Mode: that would presumably work without the need for authentication.
Apple will be partnering with vehicle manufacturers for CarKey, which indicates that it may be a factory-installed option much like CarPlay. CarKey requires a vehicle with NFC, so it is something that vehicle manufacturers will need to implement as CarPlay was.
It looks likely that luxury car brand BMW will be one of the first automakers to support the feature,
BMW teased the future of digital keys “Today, it is already possible to lock and unlock the vehicle, start the engine and share the key with others using the BMW Digital Key as part of BMW Connected on the smartphone. But this is only the first step in a global technological transformation being shaped and led by the BMW Group.”
It is unclear when Apple plans to make CarKey available to the public. The feature is not activated in iOS 13.4, released earlier this week. CarKey could be introduced in a future update to iOS 13 or held until iOS 14, which should be announced in June at WWDC.