Z-Wave secure?

[Paulusch]

How secure is the z-wave protocol?
If someone can explain in technical terms, please do. (like what sort of encryption is used? Or what else?)

I know that stuff like Klik-Aan-Klik-Uit is just a 1-way communication. So, no acknowledgement signal from receiver. And it's not secured at all.
But products that use the z-wave protocol are using 2-way communication, so both sender & receiver 'talk' to each other, so to say. And it is much more secure, but how secure, in what way exactly?

[Soepkip]

It is secure in a way comparable to "WPS" security on your wireless network.
Z-wave modules and controllers have to be "included" in one and the same network before then can communicate with each other. So you will have to enable "inclusion" mode on both the Zwave module (switch, sensor, or so) AND the controller before any module can be included in your network.

As far as I know, it is not possible to enable the inclusion mode wireless, so one needs physical access to any Zwave device to enable to inclusion mode.

[jrkalf]

The question above triggered me to do a little "lmgtfy" action and I found this article: http://www.zwaveworld.com/ask/ask27.php

Could you please explain the level of security in Z-Wave? What is the level of encryption in the protocol?
The Z-Wave technology provides for AES128 link protection. Additional security is provided by the fact that one must be in physical possession of a node to include or exclude it from a network. Most “secure” applications embed secure information frames inside the Z-Wave transport payload something like rolling code or keylock as an additional level of security.

Like kippesoep says, you'll need physical access to the device in order to set it to include or exclude mode. Unlike the WPS protocol for wifi, which is proven to be hackable (only recently, december 2011), physical access to the device is much harder to gain. (This can be annoying with wall mounted devices, but it's worth the added security )
Even if somebody wants to hack itself as master into your network, he'd need to have access to your primary master and have access to it for at least 3-5 minutes with some management tools like Ztool from Homeseer. He'd need to include his controller into your network as secondary controller and (if required) promote his controller to primary master. This takes somewhat skill, access to the management software and above all physical access. If he/she tries to take control of your network through one of your slave devices, he'd only "steal" the control of that slave device.

This is about as much as I know of this.

[Post-IT]

Please be aware that only Z-wave v4 (400-series chipset) has encryption. The last time I checked v4 modules are not default yet and most used module are v3.

Z-wave v3 has no encryption and only use a 32-digit housecode in the same way KaKu does. If someone wants to abuse your system a simple test script would work to find the house code.

[Post-IT]

Some extra details as I start remembering my conversation with Bent Sorensen from Zensys, the encryption capability is available in the 400 series chipset. It is up to the manufacturers to implement it in their devices, so having the 400 series chipset does not imply active encryption.

The only thing I didn't discuss back then was the mixed usage of 200, 300 and 400 series chips in the same network when using encryption. It could easily be that 400 chips will disable their encryption to interact with other legacy chipset versions in a similar way WiFi downgrades to legacy protocols to interact with older technology in the same network. This could mean a single legacy chip in your network will disable encryption throughout the Z-wave network.

So if you are really want things secure and use Z-wave for critical parts of your home automation, an extra call to your manufacturer or Zensys would be worth the effort.

Can you imagine many US residents already use Z-wave front door locks?...

P.S. this is the reason I skipped Z-wave and stayed with a wired solution after dumping Xanura.

[Paulusch]

Ok, I'm a bit confused...
Z-wave always uses 128-bit AES encryption for link protection, isn't it?
What is the encryption difference of the v4 chip then, opposite to the previous chips?

Are there currently any known z-wave products available (for example from Duwi of Merten)
that uses the Z-wave v4 (400-series) controller chip with the encryption feature enabled?

[Post-IT]

The earlier Z-wave chips had 3DES (56-bits) encryption which pretty much nobody used in their applications. 200 and 300 series chips have none. 400 series does have encryption on board. That is all there is in the documents from Z-wave.

If you say some sort of 128-bits AES is used, I would be wondering what for and how the implementation is done by that manufacturer. I think it is only possible on the 400 series. So it's best to ask the manufacturer for details on:

- what chips they use
- if they don't use 400 series then for what part of the communication they use encryption (authentication, authorization and full communication)
- how that encryption is implemented and supported by the hardware

Only then can you start evaluating the effectiveness of the encryption.

i.e. only encryption on the link setup would only encrypt keyexchange and not further communication. Making it in fact useless, but "encrypted" for marketing purposes.

[Paulusch]

OK, nice answer,
it's a pity that we have to ask the manufacturers for such details.