Last night I was reading more about the system architecture of @MidnightNetwork then unexpectedly encountered a rather interesting detail that few analyses mention. Midnight is built on the Substrate SDK — the same toolkit that the Polkadot ecosystem uses to create parachains. However, Midnight is not a parachain.
This may sound simple but the technical consequences are not trivial. Parachains on Polkadot benefit from shared security from the relay chain, meaning the entire validator set of Polkadot protects them. Midnight chose a completely different path. They define themselves as a partner chain with Cardano, using Substrate merely as a framework to build infrastructure without relying on any relay chain security.
In terms of consensus, Midnight combines two components.
GRANDPA is responsible for finality — meaning that when a block is confirmed, it cannot be reversed.
AURA handles block production in a round-robin manner, with validators taking turns to produce blocks according to fixed time slots.
This combination is quite stable and has been proven over many years of operation in the Polkadot ecosystem.
One interesting point is that SubWallet, the official wallet of the Polkadot ecosystem, has integrated and recognized Midnight. This shows that even though it is not a parachain, the Polkadot community still sees Midnight as an extension of the Substrate ecosystem. Developers familiar with Substrate can participate in development on Midnight without needing to relearn everything.
Meanwhile, the relationship with Cardano is on a different level. Future Cardano SPOs will be able to register as Midnight block producers through smart contracts on Cardano. They will be chosen based on the ADA stake they manage. ADA delegation does not move and remains on Cardano as usual. This is quite an innovative multi-resource consensus model that combines the strengths of both communities.
However, I have a concern. Not using relay chain security means that Midnight must take full responsibility for its own security. In the current federated phase, the validator set consists of only about 4-6 entities. Compared to the thousands of validators of the Polkadot relay chain or the hundreds of SPOs running on Cardano, this number is too small. The theoretical attack vector is much broader compared to real parachains.
The question arises as to when and how the validator set will expand sufficiently to create real decentralization?
We probably have to wait for the Mohalu phase in Q2 to know the specific direction.