Towards Fuzzy Private Set Union

In this talk, I will present the work from my Master’s thesis, where the research focuses on designing a protocol for Fuzzy Private Set Union (FPSU), a cryptographic protocol that enables two parties to compute a private union of their respective sets without leaking their intersection. In our construction, the functionality supports approximate matching based on a distance threshold, while ensuring that the server learns only the result of the union and nothing more. Our goal is to propose a formalization of an Oblivious Key-Value Retrieval (OKVR) as a building block and a protocol design of a FPSU which uses the OKVR and the hyperball projections idea from van Baarsen and Pu (Eurocrypt '24) to enable practical fuzzy unions with privacy guarantees in the honest-but-curious setting.