Zero-Knowledge (ZK) proofs, or cryptographic methods that allow one party to prove to another that something is true without revealing any sensitive underlying private information, have been a hot topic of discussion among crypto veterans. Last week’s zkDay event at EthCC Paris saw over 2,000 attendees arrive at the small venue off Rue l’Aubrac to check out ZK’s latest projects on display. P0x Labs, the developer behind the ZK Manta Network protocol, even announced a $25 million raise during the event.

Currently, this technology plays a key role in powering Layer 2 solutions. By computing a simple cryptographic proof at Layer 2, transactions can be completed almost instantly, while the record is simply sent back to the underlying blockchain as a concise proof. At the same time, ZK evidence can enable private transactions that do not transmit sensitive information to observers.

In an interview with Cointelegraph during zkDay, Tiancheng Xie, CTO of the ZK Polyhedra protocol, outlined another application of the emerging technology in the field of cross bridges. The Polyhedra team reports that the protocol has more than 50,000 daily active users and 800,000 monthly active users since its launch on the mainnet in April.

Cointelegraph: I think the ZK bridge is quite unique among all the ZK companies we’ve seen so far. Could you elaborate a bit?

Tiancheng Xie: We build a [ZK] a bridge that connects more than 10 different layer 1 and 2 blockchains. Since we use zero-knowledge proofs to prove state, our security is based entirely on proof security and source chain security. So basically, if none of them are compromised, our security won’t be compromised.

CT: What is the advantage of building something like this over an interchain like the Cosmos SDK?

TX: One big advantage is the price. So as you know, ZK can provide scalability to blockchains like roll-ups and compress user requests into a single transaction. For example, if two or three users will send messages to Ethereum. We can combine these messages to create one single piece of evidence. And the price of gas remains the same. So if more users join the batch, they can all get free proofs.

CT: Interchain is still a very new technology and unfortunately we have seen several security incidents involving it. So how does the Polyhedra ZK bridge solve this problem?

TX: So zero [knowledge] a proof cannot be broken because it has already been proven to be true. Another is the security of the source chain, which is very hard to crack because, for example, to break the source chain, you have to break Ethereum first [the underlying chain], which is very difficult. I think the foundation is very solid compared to other chain protocols where you can rely on a set of computing nodes. However, this is not very secure because the transaction volume can be very high, up to 200,000 or 300,000 per day, so it is possible that attacks against nodes will be masked.

CT: The sector is changing very quickly. Do you think the developers’ knowledge has caught up with the ZK technology they are trying to build?

TX: So if you look at AI, the advancement of AI, we’re actually going down a similar path. Every year we make better tools and the developers keep getting better and better. So eventually these tools will be easy to use for the web. So I think the gap should be very small.

zkDay Paris Main Stage | Source: Cointelegraph

This interview has been edited from its original format for clarity.