报告人：刘富康

报告地点：淦昌苑D305

报告时间：2024-10-10 15:30

报告摘要：

A new design strategy for ZK-friendly hash functions has emerged since the proposal of Reinforced Concrete at CCS 2022, which is based on the hybrid use of two types of nonlinear transforms: the composition of some small-scale lookup tables (e.g., 7-bit or 8-bit permutations) and simple power maps over GF(p). Following such a design strategy, some new ZK-friendly hash functions have been recently proposed, e.g., Tip5 and Monolith family. Using the composition of some small-scale lookup tables to build a large-scale permutation over GF(p) -- which is called S-box for convenience -- is a main feature in such designs, which can somehow enhance the resistance against the algebraic attacks because this large-scale permutation will correspond to a complex and high-degree polynomial representation over GF(p). In this talk, I will show a novel technique to study the differential properties of such special S-boxes over GF(p), and apply it to efficient collision attacks on round-reduced Tip5 and Monolith family.

报告人简介：

Fukang Liu obtained his PhD from East China Normal University in 2021, and is working as an assistant professor at Tokyo Institute of Technology. His main research interest includes hash function and MPC/FHE/ZK-friendly symmetric-key primitives. For his research achievements, he has published several papers at top international conferences including FSE、CHES、ASIACRYPT、EUROCRYPT and CRYPTO. In particular, he also received the best-paper award at FSE 2022.

邀请人：胡凯

审核人：魏普文