An (Almost) Constant-E ort Solution-Veri cation Proof-of-Work Protocol based on Merkle Trees

Abstract : Proof-of-work schemes are economic measures to deter denial-of-service attacks: service requesters compute moderately hard functions that are easy to check by the provider. We present such a new scheme for solution-verification protocols. Although most schemes to date are probabilistic unbounded iterative processes with high variance of the requester effort, our Merkle tree scheme is deterministic, with an almost constant effort and null variance, and is computation-optimal