As a leading public chain designed for commercial use, Ultrain is excited to see that Polkadot is experimenting new approaches to improve the interoperability of public chains. On July 22nd, our chief architect Yufeng Shen, and Ning Li, our CTO, talked with Gavin Wood, the creator of cross-chain project Polkadot, and Alistair Stewart, a researcher at Web3 foundation.

Q1: Ultrain is considering connecting to the Polkadot system. Given the development should be completed in three months, which approach should we choose? Can we write a smart contract on an existing parallel chain (e.g. Edgeware) to handle the data I/O? Will we need to bid a new parallel chain to do that?

Gavin Wood: Writing smart contracts on an existing parallel chains has the advantage of lower development cost in the early stages. However, the parallel chain may not support the algorithm required by Ultrain (e.g. BLS aggregate signature). We will consider providing a common bridge chain for public chains to use when the main-net online.


Q2–1: Will a validator need to store the world state in every parallel chain?

G: They don’t. The validators will be stateless and collators will construct the next block. All data needed for transactions and state changes will be included in the block.

Q2–2: If the transaction accesses a huge amount of data, then the size of the transaction / block could become unbearable?

G: Yes, we will need an economic model to ensure that too much data cannot be involved in the execution of a transaction.

Q3: In your opinion, will there be a chain in the future that may satisfy all needs? Will we still need cross-chain services if such a public chain exists?

G: I think it’s impossible, because there will always be customized requirements, and a chain is unlikely to meet all the needs; so the way to go is to lower the cost of developing a chain with substrate, and then these chains can be linked together.

Q4: Can a large number of small chains be added together to fight a single chain with a big ecology?

G: There is network effect here as the number of small chains grows. When people designed the Internet protocol, there is no concern of centralization, so the big companies, such as Facebook, Alibaba, Twitter got stronger. In the blockchain world, the situation should be changed, VC should pay more attention to small blockchain companies.