Date: August 27, 2025

Time: 3:45-5 p.m.

Location: Computing and Information Science Building, Room 450 or via Zoom

Speaker: Ziyi Guan, EPFL

 

A color photo a woman sitting on the beach looking back over her left shoulder.

 

Title: Breaking Verifiable Delay Functions in the Random Oracle Model

Abstract: A VDF is a cryptographic primitive that requires a long time to compute (even with parallelization), but produces a unique output that is efficiently and publicly verifiable.

We prove that VDFs do not exist in the random oracle model. This also rules out black-box constructions of VDFs from other cryptographic primitives, such as one-way functions, one-way permutations and collision-resistant hash functions.

Based on https://eprint.iacr.org/2024/766, joint work with Artur Riazanov and Weiqiang Yuan.