Paper 2022/520

Efficient Verification of the Wesolowski Verifiable Delay Function for Distributed Environments

Vidal Attias and Luigi Vigneri and Vassil Dimitrov

Abstract

Verifiable Delay Functions (VDFs) are a set of new crypto- graphic schemes ensuring that an agent has spent some time (evaluation phase) in a unparalleled computation. A key requirement for such a construction is that the verification of the computation’s correctness has to be done in a significantly shorter time than the evaluation phase. This has led VDFs to recently gain exposure in large-scale decentralized projects as a core component of consensus algorithms or spam-prevention mechanisms. In this work, due to the increasing relevance and the lack of literature, we will focus on the optimization of the verification phase of Wesolowski’s VDF and provide a three-axis of improvement concerning multi-exponentiation computation, prime testing techniques, and hash- ing tricks. We will show that our optimizations reduce the computation time of the verification phase between 12% and 35% for the range of parameters considered.