Is Polybase limited to a specific chain?

It is chain agnostic. We're writing our zero-knowledge proofs, and content hashes on-chain, by building a bridge between Polybase and various L1s and L2s. We're starting with EVM-based chains first and then we have partnerships that we're building with a couple of other permissionless ecosystems as well. But it is agnostic and we'll be partnering with ecosystems to make a bridge available.

When you have off-chain data, let's take the example of one of our customers.

They're building a CRM tool for web3. Now the CRM tool is supposed to allow, let's say, hundreds of thousands of people to collaborate on a sales process or on an investment process for a project. You can imagine there's like the rows representing different projects and columns representing potential stages that the project is going through or other metadata on that project.

So when you have a tool like this or other use cases for Polybase, all of these stay off-chain in the Polybase indexer, which is a node on the Polybase network, similar to Filecoin, where you have different service providers storing your data. Now what happens is every time you write data into the Polybase database, we create a zero-knowledge proof that that data was written correctly, respecting that database's permissions.

Now, this proof then gets written on-chain and then the data off-chain gets rolled up into a Merkle tree, which is a kind of hash of that data. Then a hash gets written on-chain as well. So now what you have is you have off-chain data, but you have on-chain proof that the data was written correctly and then you have a final rolled-up hash of this off-chain data. Now what that allows you to do is from a smart contract, you can query that off-chain data, and then you can validate that the data you received back is correct by reading the on-chain proofs and content hashes.

And so that end-to-end validation of querying large amounts of data and then being able to prove that this data is the data that you wanted and that it hasn't been tampered with and has been written with the right permissions. That's the interaction of on-chain and off-chain components that Polybase allows.