Secure Multi-Party Sorting and Applications

Sorting is among the most fundamental and well-studied problems within computer science and a core step of many algorithms. In this article, we consider the problem of constructing a secure multi-party computing (MPC) protocol for sorting, building on previous results in the field of sorting networks. Apart from the immediate uses for sorting, our protocol can be used as a building-block in more complex algorithms. We present a weighted set intersection algorithm, where each party inputs a set of weighted elements and the output consists of the input elements with their weights summed. As a practical example, we apply our protocols in a network security setting for aggregation of security incident reports from multiple reporters, specifically to detect stealthy port scans in a distributed but privacy preserving manner. Both sorting and weighted set intersection use O ` n log2 n ´ comparisons in O ` log2 n ´ rounds with practical constants. Our protocols can be built upon any secret...

• Type: Journal
• Year: 2011
• Where: IACR
• Authors: Kristján Valur Jónsson, Gunnar Kreitz, Misbah Uddin
• Keywords: Anomaly Detection, IACR 2011, Input Elements, Sorting Networks