The Application of zk-SNARKs in Full-Chain Games: Taking PopCraft as an Example

PopCraft is an on-chain elimination game where players need to eliminate all elements on the board within 4 minutes to earn token rewards. However, due to its on-chain nature, every player action requires interaction with the blockchain, leading to longer wait times that significantly impact the gaming experience.

To solve this problem, we considered using zk-SNARKs technology (ZKP) to reduce the frequency of interactions between players and the blockchain. The initial idea is to keep the game process off-chain, but ensure there is no risk of cheating through some mechanism. Specifically, every action taken by the player in the game generates a ZKP, with the ZKP of the subsequent action generated based on the ZKP of the previous action, forming a self-contained ZKP that resembles a blockchain structure. At the end of the game, the ZKP of the last action is sent to the chain for verification by a smart contract.

However, after further research, we found that this solution faces multiple technical challenges:

1. Anti-cheating for the game process and results: Both the game process and results need to be verified simultaneously.

2. The technical challenges of incremental generation of ZKP: Each step of ZKP relies on the previous step, making the verification process complex.

3. ZKP consistency verification: How to ensure the consistency of each ZKP with the previous ZKP has not yet found a clear solution.

4. Handling of Public Game Data: The game data of PopCraft is public, and using zk-SNARKs for information hiding seems unnecessary.

5. Game item consumption issue: How to handle operations involving Token transfers within the ZKP framework is still a challenge.

After in-depth analysis, we have drawn the following conclusions:

For scenarios like PopCraft that do not require hiding game data, using zk-SNARKs for information concealment may introduce unnecessary complexity. The key to enhancing the gaming experience lies in finding a way to ensure that the entire process from start to finish of the game is free from cheating, while only validating the final result on-chain.

Currently, it seems that ZKP technology is mainly applicable to two types of scenarios in the gaming field:

1. Information hiding in incomplete information game types, such as Dark Forest, Texas Hold'em, etc.

2. Proof of single-step game results, such as lotteries, guessing numbers, etc.

However, for games like PopCraft that require verification through multiple steps and the entire process, the application of ZKP technology still faces many challenges. This field still requires more technological innovation and practical exploration.