The slow trickle of HomeKit-compatible accessories is reportedly linked to a high level of encryption mandated by Apple, said to be generating unusuable levels of lag in prototype Bluetooth products.
HomeKit encryption standards require that accessories use 3,072-bit keys, and Curve25519, an elliptic curve for signatures and key exchange, according to Forbes. While this is manageable for devices communicating via Wi-Fi, ones using Bluetooth Low Energy (LE) are said to be running into processing barriers.
A spokesman for Elgato commented that one Bluetooth-based sensor it had in development was initially taking up to 40 seconds to determine if a door was open or closed. An anonymous source at another company meanwhile claimed that lag reached up to 7 minutes on a device.
The second person remarked that various makers of Bluetooth LE chips — like Marvell and Broadcom — are working to improve their designs to handle Apple's encryption demands. Apple itself is allegedly aware of the lag problem.
In the meantime, Elgato is coping via optimized firmware and extra onboard memory, and planning to sell its workarounds to other accessory makers. To date, the company is the only HomeKit accessory maker with Bluetooth products.
Other obstacles are allegedly hampering HomeKit development as well. Forbes' sources said that HomeKit code wasn't at a level for MFi (Made for iPhone/iPod/iPad) certification until two months ago, and Apple insists that every change to a product be resubmitted. The latter issue is relatively normal for the MFi program.
Apple's encryption demands are presumably a way of deflecting any worries about using HomeKit products. Whereas someone hacking into an iCloud account might gain access to photos, contacts, and important documents, hacking into a HomeKit network could open up real-world access to someone's home or cause havoc with lighting and appliances.