Experimental Comparisons of Verifiable Delay Functions

Verifiable delay function (VDF) has been a hot topic in recent cryptography research since the Ethereum researchers announced that they intended to use it in Ethereum 2.0. VDF has many applications in decentralized systems. This paper tries to organize the development path of VDF and related applications. We compare the performance of the four state-of-art VDFs by theoretical analysis and experimental verification. And through experiments, the influence of different type of groups and different hardware conditions on VDF performance are compared. In the end, we concluded that Wesolowski VDF is more suitable for decentralized clock applications that require higher time accuracy. Meanwhile, modular N multiplicative cyclic group is more suitable for constructing VDF that requires higher time accuracy while the class group is more suitable for applications with limited space. Besides, the effect of hardware on various VDFs is basically the same if the four VDFs use the same group and in the case of the same number of evaluation steps. Generally speaking, it might have a constant multiple improvement on the performance of VDF.