HomeKit security with Apple TV
HomeKit securely connects some third-party remote accessories to Apple TV and supports adding user profiles to the owner of the home’s Apple TV.
Using third-party remote accessories with Apple TV
Some third-party remote accessories provide Human Interface Design (HID) events and Siri audio to an associated Apple TV added using the Home app. The remote sends the HID events over the secure session to the Apple TV. A Siri-capable TV remote sends audio data to Apple TV when the user explicitly activates the microphone on the remote using a dedicated Siri button. The remote sends the audio frames directly to the Apple TV using a dedicated local network connection. A per-session HKDF-SHA512 derived key-pair that is negotiated over the HomeKit session between Apple TV and the TV remote is used to encrypt the local network connection. HomeKit decrypts the audio frames on Apple TV and forwards them to the Siri app, where they are treated with the same privacy protections as all Siri audio input.
Apple TV profiles for HomeKit homes
When a user of a HomeKit home adds their profile to the owner of the home’s Apple TV, it gives that user access to their TV shows, music, and podcasts. Settings for each user regarding their profile use on the Apple TV are shared to the owner’s iCloud account using iCloud end-to-end encryption. The data is owned by each user and is shared as read-only to the owner. Each user of the home can change these values in the Home app and the Apple TV of the owner uses these settings.
When a setting is turned on, the iTunes account of the user is made available on the Apple TV. When a setting is turned off, all account and data pertaining to that user is deleted on the Apple TV. The initial CloudKit share is initiated by the user’s device and the token to establish the secure CloudKit share is sent over the same secure channel that is used to sync data between users of the home.