Challenge Game Protocol
The challenge game protocol is the interactive process used to resolve disputes regarding the validity of a state transition in optimistic rollups. When a fraud proof is initiated, the protocol executes a multi-step game between the challenger and the sequencer to identify the exact point of divergence in the computation.
This often involves a bisection method, where the parties iteratively narrow down the disputed execution trace until a single, atomic instruction is isolated. The base layer then executes this specific instruction to determine which party is correct.
This method is highly efficient as it avoids re-executing the entire batch on the expensive layer one chain. The challenge game ensures that disputes are resolved in a deterministic and transparent manner, upholding the network's state.
It is the technical backbone of optimistic fraud proofs.