A smart key is a digital key stored on your phone or watch that unlocks, locks, and even starts compatible cars, homes, and hotel rooms without a physical key. Unlike a traditional metal key or a key fob, a smart key uses technologies like NFC and ultra-wideband to communicate with a lock or vehicle when you hold your device nearby.
What is a smart key?
A smart key is a broad term that covers two main types of keyless access. The first is the traditional wireless fob for cars that uses radio frequency identification (RFID) and proximity sensors to allow keyless entry and push-button start. The second, and more recent, type is a digital key stored in a phone wallet, like Apple Wallet or Google Wallet, that works for vehicles, homes, and hotel rooms. Apple's iPhone guide says you can store digital keys to your home, hotel room, car, and scooter in Wallet. These digital keys replace the physical fob or card with your smartphone or smartwatch.
How traditional automotive smart keys work
Traditional automotive smart keys rely on RFID technology, proximity sensors, and encryption. A microchip inside the key fob communicates wirelessly with the car's onboard computer. When the driver approaches the vehicle, the proximity sensor detects the key fob's presence and initiates an unlocking sequence. Because the communication is encrypted, the system verifies that only an authorized key is requesting access. This allows the driver to unlock the doors and start the engine by pressing a button, without ever inserting a physical key into the ignition.
Digital car keys on iPhone and Apple Watch
To use a digital car key on an iPhone or Apple Watch, you add the key to the Wallet app using the car manufacturer's instructions. Apple requires a compatible car, an iPhone XS or later or iPhone SE (2nd generation) with the latest iOS, or an Apple Watch Series 5 or later or Apple Watch SE with the latest watchOS. You must also be signed in with your Apple Account. Once added, you can unlock, lock, and start a compatible car by holding your iPhone or Apple Watch near the vehicle's NFC reader. Apple Watch support says home keys work by placing the device near the lock, and car keys can unlock, lock, and start a compatible car with iPhone or Apple Watch.
Digital car keys on Android and Samsung devices
Digital car key support on Android is available on select devices running Android 12 and later. Google lists supported devices as Pixel 6 and later, including Pixel Fold, and select Android devices. Pixel Watch 3 and later also support the feature. For Samsung devices, BMW's Digital Key Plus is available on compatible Samsung devices running Android 13.1 or later and Google devices running Android 13.1 or later, but only for BMW vehicles produced from November 2022. BMW's official announcement says BMW Digital Key Plus on Android is available on compatible devices from Samsung or Google. The exact setup steps vary by car maker and device.
Smart keys for your home and hotel room
For your home, you can add a smart key to Apple Wallet by adding a supported lock to the Home app on your iPhone. After adding the lock, you choose an unlocking option and can set automations such as "Lock After Door Closes" and "Lock When Leaving Home." For home keys, Apple Watch documentation says to add a supported lock to the Home app on your iPhone, choose an unlocking option, then choose automations such as "Lock After Door Closes" and "Lock When Leaving Home." Once set up, you unlock the door by placing your iPhone or Apple Watch near the lock. For hotel rooms, you add the key from the hotel provider's app at participating properties, then use your iPhone or Apple Watch to unlock the room. Apple automatically presents the right key when you arrive at your door or vehicle using NFC.
Limitations and compatibility
Car compatibility varies by manufacturer, so you must confirm with the dealership or car maker that your vehicle supports digital car keys. Home key support depends on the lock maker, and hotel key availability is specific to each participating property. There is no universal app that works across all platforms; the app and setup path depend on the key type and vendor, such as Wallet, Home, hotel provider apps, or a car maker's system. If you need a device-by-device fact sheet for iPhone, Samsung Wallet, and Google Wallet, the exact supported models and menu paths are documented by each manufacturer.
Frequently Asked Questions
Can I use a smart key for more than one car?
Yes, you can store multiple car keys in your phone wallet, but each key must be added separately from the car manufacturer's app or instructions, and each vehicle must be compatible with your phone's digital key system.
What happens if my phone battery dies?
Some digital car keys have a power reserve feature that lets you use NFC to unlock and start the car even when your phone battery is dead, but this depends on the car maker and phone model. For home and hotel keys, you may need a backup physical key or card.
Is a digital smart key more secure than a traditional key fob?
Digital smart keys use encryption and authentication that can be more difficult to clone than traditional RFID fobs, but they also introduce new risks such as phone theft or unauthorized access if your device is compromised. Always use a strong passcode and enable two-factor authentication on your phone.
Can I share a digital car key with family members?
Many car makers allow you to share digital keys with other people through the manufacturer's app, letting them add the key to their own phone wallet. The sharing process and number of allowed users vary by car brand.
Do all smart locks work with Apple Home Key?
No, only locks that specifically support Apple Home Key can be added to the Home app and stored in Apple Wallet. Check the lock manufacturer's specifications before purchasing.
For the wider topic, see location tracking and NFC.
