I was working on a Matter device but it never got certified due to high cost/lack of customer demand.
Matter states that firmware images “may be encrypted.” This is not a requirement, though encryption is allowed and may add security
(https://community.arm.com/arm-community-blogs/b/internet-of-...)
Disclaimer: I haven't tried serial flashing of Shelly/Sonoff Matter-enabled devices myself, just remember some complaints of customers that failed to re-flash such devices.
can you explain what you mean by this?
Also: the Apple home app can’t change their mode to matter, you have to do that in home assistant.
The part about Matter that's "closed" is the device attestation process; the Distributed Compliance Ledger (DCL) contains a closed set of trusted Product Attestation Authorities. The device's Device Attestation Certificate (DAC) needs to chain to these PAAs for a "production" Matter Commissioner to enroll the device in a fabric without additional steps.
Here's he thing: all available Matter Commissioners make it really easy to commission a device with an untrusted DAC; for Google you need to add the IDs for the device to a Developer account associated with device you're trying to use as the Commissioner, and for Apple (at least as of a year or so ago when I last tried this), you just press "Trust this untrustworthy device" on a dialog box.
* The list of officially trusted companies and root certificates is stored on a blockchain, for whatever reason, but at least this way it's a fairly open list and it's supposed to be shared equally across all vendors.
* It's a lot easier to get an official key provisioned / device certified. It's not like UEFI where there's some murky trusted set of root keys belonging to a major manufacturer (Microsoft) who blesses things at a whim.
Importantly:
Even if the "vendor" (in this case, it's Google/Apple) stopped supporting test keys in their Commissioner, one could still run a "fully private" Matter fabric with their own Commissioner. Of course, if this happened, a user couldn't commission their devices onto the walled garden Google Home / Apple Home ecosystems, but, they could still make their own Matter fabric with their own Controller. It's not done this way normally: even with HomeAssistant, which can run its own Matter Controller, the Commissioner role is typically delegated to Apple/Google SDKs through the Home Assistant app. But this is because it's a huge pain to develop a working Commissioner (due to Bluetooth, mostly), not because it's not possible. There's no "lock-out" that causes Matter devices to only provision to approved Controllers/Fabrics - the lock only goes the opposite direction, to prevent end users from buying insecure/spyware devices with the Matter label.
However, unfortunately:
* You don't really enroll your own key or root certificate with most of the "standard" (Apple/Google) Commissioners to use them with development devices - rather, you use a fixed set of vendor or device IDs which signify them as test devices (in the extra easy path, you even use a fixed device certificate for a Test Device). This makes sense from the constraint that users can still build and develop their own devices while protecting the ecosystem from "rogue vendors," but it's not like UEFI Secure Boot in this case where the end user can enroll their own keys and truly control the system end to end.
Now again, there's nothing stopping the end user from building a Commissioner which would trust their own self-signed certificate, besides it being a pain in the butt, but that's not how it works by default - it's truly a development mode, not a bring-your-own-keys.
... what?
All it means is that the "commissioner" (broker which attaches Matter devices to your Fabric) ignores the chaining of the device attestation to an approved CA. In the case of using Google's Commissioner, this requires adding a Vendor and Product ID in your account's Developer console. In the case of Apple's Commissioner, it's just pressing a "Trust this unknown device" button. That's it.
I personally think the worst part of this is that China manufacturers are less likely to produce Matter/Thread equipment.
Cheap China equipment has been great for Zigbee adoption. They're much less reliable, but fantastic for getting a smart home going for cheap.
Some manufacturers also make Z-wave devices, like this[3], which has some generic low-voltage inputs and outputs.
So while not as trivial as other things, it's possible to do a lot of DIY stuff.
[1]: https://z-wavealliance.org/development-process-overview-2/
Sorry, it’s a closed ecosystem. It relies on PKI and device attestation to ensure that only devices from approved partners are usable. It’s unlikely that small players can participate, and zero chance of any homebrew scene.