The Ethereum Foundation announced a new technical challenge called evm.fast, aimed at establishing a finite worst‑case step bound for verifying Ethereum blocks on a 64‑bit RISC‑V model. The current baseline score is infinite, meaning no uniform bound has yet been proven.
Challenge details
Participants must produce a certified upper bound, denoted K, on the number of execution steps required for block verification. The bound must apply to every input covered by the challenge and include startup steps, preventing contestants from omitting warm‑up costs.
The verification model runs through Flapjack, a Lean 4 adaptation of the Pancake compiler designed for a 64‑bit RISC‑V architecture. Lean 4 serves as a proof assistant that checks mathematical proofs line by line, while RISC‑V provides the instruction set for the processor model.
Purpose and relevance
The effort supports the Foundation’s broader zero‑knowledge proof agenda, which seeks to enable provers to demonstrate correct computation without re‑executing the entire process. Many zkVM systems compile code to RISC‑V, making a uniform step bound valuable for predictable proving costs and recursion soundness.
Recent improvements have reduced latency for real‑time proofs of full Ethereum blocks from roughly 16 minutes to under 10 seconds for 99% of mainnet blocks on target hardware. A proven bound K would allow provers to budget for the hardest possible block rather than relying on empirical estimates.
Security implications
A certified worst‑case ceiling helps mitigate denial‑of‑service risks, as attackers would find it harder to craft blocks that exceed the known step limit. With the baseline at infinity, the first valid finite bound will automatically become the winning entry, after which the competition will focus on tightening K.
Additional context
The challenge complements ongoing Foundation work on security estimation, guest‑program verification, and RISC‑V semantics in Ethereum execution. Guest programs refer to the code that a zkVM runs and proves, specifically the logic that checks an Ethereum block.
