Optimizing Optimism: Up to 3.5x Faster zkVM Validity Proofs via Sparse Derivation

The Optimism derivation pipeline is engineered for correctness and liveness, not for succinct validity proofs. A straightforward port to a zkVM imposes significant overheads, making validity proofs significantly more costly than necessary. We systematically identify inefficiencies in the current design, analyze their impact on proving costs, and provide a soundness-preserving redesign tailored to zk proving. Our redesign achieves up to 6.5x faster derivation inside zkVMs (3.5x overall speedup) while maintaining identical safety guarantees.