Blockchain usage in smart home

Question

I am currently gathering information for my thesis about smart home implementaton with a use of blockchain. The blockchain usage is a requirement from my thesis supervisor and I have huge problem with finding out how blockchain technology may be useful in home automation.

What I have already considered is that there are two types of blockchain which I can use: private and public.

The public blockchain won't be useful at all, because of long time to achieve consensus and every transaction costs money (fee for miners).

I also don't see any adventage of private blockchain over regular database in such application. There are two reasons:

-I won't be able to store blockchain on every smart home device, because they all have limited space. So If I need to store blockchain in some centralised way, I think it looses it's immutability adventage.

-The public key cryptography is a very nice thing, but I can archieve that also in a regular database, so I don't see the need to implement blockchain for that.

So am I not seeing something? How use of blockchain may be helpful is such a small project?

Thanks in advance for any advice! :)

Answer 1

The only purpose I see of blockchain in IoT is access control. You go over this briefly in the last note regarding public key cryptography, but the database obviously adds a centralization point. You can easily do the public key aspect without any sort of aspect, by just setting up the IoT device with the public key from a keypair you create. Only signatures from your account can operate the devices, as well as give access to other keypairs to access the devices.

The difficulty with doing cryptography without a database is with access removal. It's easy to give access by just signing something with your authorized account, but then how do you take away access? You have to have some immutable history to prove you removed access. Using a public ledger for this adds interoperability (i.e. allows different vendors to use the same account based authorization system).

A smart home hub could probably just operate as a light client instead of having to download the whole blockchain as well.

Answer 2

You can think of this example. When people talk about Home Automation, it deals with personal data like the door lock, lights on/off, heart beat from smart watch etc. When you talk about a Blockchain, the need for various nodes that provide some transnational data is the common expectation. So in order to combine these two technologies, you might want to think out side of Home Automation like say a society or a community grid.

Assume 20% of houses in the community have solar panels installed for their houses. They wish to share the electricity generated from their solar panels with the community, now all the houses in the community are in a private blockchain and the electricity produced and consumed is in the blockchain which is immutable. May be there are other houses which are in some other transaction for may be a shared garden maintenance, water usage etc. You get the idea, so the billing is automated and there is that benefit.