An Efficient Non-Interactive OT-MP-PSI Protocol for Multi Institution Attack Detection

Abstract

The Over Threshold Multiparty Private Set Intersection (OT-MP-PSI) problem is a cryptographic problem where N participants aim to identify elements that appear in at least t sets without revealing information about elements that do not meet this threshold. This protocol is particularly relevant for detecting multi-institution attacks, which require private and efficient information sharing. In order to detect the attackers, the institutions want to identify the common external IPs among other institutions without leaking the rest of the connection data. Existing solutions either require numerous communication rounds or have impractical computational complexities for large datasets. We introduce a non-interactive OT-MP-PSI protocol optimized by a novel hashing scheme with a computational complexity of O(t^2 M (N choose t)) as compared to the O(M(N log(M)/t)^{2t}) computational complexity of previous existing solutions.

Experimental benchmarks using real-world network data demonstrate the protocol's practicality, showing significantly faster reconstruction times compared to existing methods and effective scalability with the number of participants and set sizes.

Our protocol also efficiently solves the two-party private set intersection (N=t=2) and the multi-party private set intersection (N>2, t=N), offering a versatile solution for various applications.