[Originally published on my blog http://blog.xojs.org/post/125719728246/mfi-and-homekit but might be of interest here]
Amazon dropped off my Elgato Eve door sensor on Friday. I don’t really need a door sensor, at least not to sense the door, but I did want a Bluetooth HomeKit device to take apart. This one is the cheapest I could find.
The device itself is unsurprising: a Bluetooth CPU/Radio combo, reset switch, magnetic sensor, led, power management, and the MFi chip. The MFi chip has been the subject of some speculation for HomeKit, and its supposed late addition to the spec the reason for product delays. But from what I can see (and based on its part number), this chip is just the same Apple’s MFi chip found in iPhone cables and adaptors. It’s not HomeKit specific. It certainly isn’t responsible the securing the communication between the device and iPhone; it just does what MFi chips always do; secure the relationship between the manufacturer and Apple.
For more information on these chips, DuckDuckGo is your friend; just search for “ipod authentication coprocessor 2.0c”.