Original author: @MohamedFFouda
Original compilation: BlockBeats
Volt Capital entrepreneurial partner @MohamedFFouda shared his views on on-chain game expansion solutions on social media platforms, and pointed out that ZK state channels are a better expansion option for on-chain multiplayer games. BlockBeats now compiles the original text as follows:
In previous discussions, I delved into the concept of horizontal scaling of applications, specifically focusing on full-chain games. For single-player games, horizontal scaling is a very suitable solution. However, for multiplayer games, zero-knowledge proof (zk) state channels become a superior scaling option. So, what exactly is a zero-knowledge state channel?
State channels are not new, in fact they were one of Ethereum’s earliest scaling solutions. The essence of a state channel can be divided into three parts: first extracting a portion of the on-chain state, then continuously updating this state off-chain, and finally submitting the final state back to the chain when necessary.
Apparently, the concept stems from an extension of the design of Bitcoin’s Lightning Network, which is essentially a payment channel. However, without zero-knowledge proofs (ZKP), the advantages of state channels are not significant. Without ZKP, all signatures authorizing changes to state (off-chain) would have to be verified on-chain, which does not significantly reduce costs compared to on-chain transactions.
Zero-knowledge proofs provide convenience for solving this problem. Participants in a state channel only need to generate an off-chain proof to verify that all their interactions and signatures are valid. This proof can be verified low-cost on-chain, resulting in significant cost savings. So, how does this relate to scaling multiplayer on-chain gaming?
Many multiplayer games, such as poker, are competition-based, that is, a group of players create and participate in game competitions, and depending on the results of the game, each persons assets will change accordingly. In this case, zero-knowledge state channels can effectively scale multiplayer games and reduce the cost of on-chain verification while ensuring the security and fairness of the game.
For this type of game, you need a shared layer to store all players assets. In each game, the details of exactly what happens are less important than the end result of the game, which is changing the asset balance. Additionally, players cannot participate in multiple games at the same time.
This makes these games ideal candidates for zero-knowledge state channels. Once the game starts, the status of participating players is locked on rollup. During the game, players generate zero-knowledge proofs (ZKPs) to prove that their actions are valid. These zero-knowledge proofs will recursively build on previous zero-knowledge proofs, and so on.
When the game ends, only the final zero-knowledge proof (ZKP) and associated state changes are submitted to the application rollup for settlement. This is because intermediate transactions (TX) are not processed on rollup, enabling up to 100x scalability. This approach also works for non-turn-based games, such as Among Us.
However, in this case, an entity is required to act as a temporary sequencer, ordering channel transactions and generating intermediate recursive zero-knowledge proofs (ZKPs). I call this situation transient L3. The main challenge faced by the zero-knowledge state channel approach is the online requirements of the channel participants. A player who quits may force remaining players to continue playing on the application rollup, resulting in higher fees for other players.
Still, this approach has huge potential, and many teams including Ontropy, Paima Studios, and cartridge are working toward it.
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