Breaking News
News & Analysis

Apple HomeKit Requires ID Chip

Plenty of IoT platforms, but all have their quirks
7/28/2015 07:00 AM EDT
7 comments
NO RATINGS
1 saves
More Related Links
View Comments: Newest First | Oldest First | Threaded View
Cuno
User Rank
Author
Re: Chip it!
Cuno   7/30/2015 4:52:02 AM
NO RATINGS
>We tested your solution and it performed flawlessly.

Very glad to hear this! Could you tell me a bit more (pfister@oberon.ch) ?

phil_water
User Rank
Rookie
Re: Chip it!
phil_water   7/30/2015 3:52:55 AM
NO RATINGS
Very interesting post! Otherwise I love the front picture of the article with pasta!

rick merritt
User Rank
Author
Re: Chip it!
rick merritt   7/29/2015 7:24:31 AM
NO RATINGS
@Cuno et al: Thanks for chiming in with your expertise!

pbleyer
User Rank
Author
Re: Chip it!
pbleyer   7/29/2015 5:41:05 AM
NO RATINGS
I think the article indeed refers to it:

The Apple-approved coprocessors and firmware provide secure communications between apps running on iOS devices and the manufacturers' smarthome gizmos.

There is more information in the net if you look around. And, as you correctly mention, the platform solutions from vendors like Broadcom, Marvell, Mxchip and integrators like Lifx, you can read in their documentation or see in their reference design schematics that they indicate the need of the Apple authentication chip for HomeKit support. Their evaluation boards either connect to a breakout board with the device (eg Marvell) or provide a footprint for the chip (eg Broadcom WICED) so end customers can directly solder development or serialized end-product chips to them.


The only (mostly) open-source solution with HomeKit support that I am aware of is the MICO platform from Mxchip. The communication with the coprocessor is obviously provided in binary form since that information is covered by the Apple MFi NDAs.

BTW, kudos for the implementation of HomeKit in the nRF51. We tried hard and we could never get the 3072-bit calculations down to the timings required by specs. We tested your solution and it performed flawlessly.


Cheers.

Cuno
User Rank
Author
Re: Chip it!
Cuno   7/29/2015 3:28:55 AM
NO RATINGS
I reread the The Register article a couple of times, and actually it doesn't really talk about the authentication chip (which is what Rick Merritt referred to in his article, the "Apple silicon").

The Register refers to certified HomeKit hardware/software solutions by chip vendors, typically a hardware development kit plus a HomeKit SDK. There are such Apple-approved offerings from Broadcom, Marvell, and as I mentioned earlier from Nordic Semiconductor.

Based on these development tools, companies can then develop their accessories, designing in one of these communication chips and the HomeKit Accessory Protocol implementation that comes with its HomeKit SDK.

The article is wrong though in some aspects. For example, such a HomeKit SDK contains no Apple firmware. HAP is implemented either by the chip vendors themselves, or our OberonHAP implementation is licensed by the chip vendors.

Cuno
User Rank
Author
Re: Chip it!
Cuno   7/28/2015 2:37:04 PM
NO RATINGS
Yes indeed. It should be well known that Apple has the MFi program for companies designing accessories for Apple devices. If a company registers for it, which is free, it can get access to the HomeKit specifications. If they do that and read them, they will not be surprised about the requirement for using the venerable Apple authentication chip as described in the Register article.

"May have triggers for geo location"? Nonsense...

To expel another common myth: the authentication chip does not process the computationally expensive parts of the HomeKit Accessory Protocol (HAP), like ChaCha20 and Curve25519. These must be executed by the microcontroller of the accessory. Unfortunately, good microcontroller implementations have only started to arrive on the market. The first generation implementations seem to be abysmally slow and memory hogs, if various recent reports on the Web can be believed. In particular, Bluetooth Low Energy accessories may have been delayed because of this, due to their typically slower microcontrollers.

However, this is not an inherent problem with HAP: our second-generation OberonHAP implementation made HAP feasible even on a 16 MHz Cortex-M0 with 32 KB of RAM, like a Nordic Semiconductor nRF51 chip (Nordic's HomeKit SDK is based on OberonHAP). And we will soon have completed an even more optimized third-generation implementation (http://oberonhap.com).

Here two official Apple sources that shed a bit more light on what they do in HomeKit:

http://devstreaming.apple.com/videos/wwdc/2014/701xx8n8ca3aq4j/701/701_designing_accessories_for_ios_and_os_x.pdf?dl=1 (slides 68 to 98) and

https://www.apple.com/business/docs/iOS_Security_Guide.pdf (page 20)

And an article with a diagram describing the HomeKit ecosystem:

http://oberonhap.com/background/

Best regards

Cuno

pbleyer
User Rank
Author
Chip it!
pbleyer   7/28/2015 12:31:38 PM
NO RATINGS
"There's no clear story what the chip does but I expect it is involved with access to the cloud and may have triggers for geo location."

Pfff.... Really? A simple web search would have hinted that it is the same "iPod" authentication co-processor vendors need to put in their devices to certify that a device is Apple-compatible. This is well known. For example, The Register posted about it a couple of weeks ago... http://www.theregister.co.uk/2015/07/13/security_apple_homekit_delays.

I don't see how this could be much different from needing any other specialized hardware to talk to other home automation systems. In particular if they have an 802.15.4 radio that requires a bridge or a dongle when using a smart phone or a personal computer.

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed