Information Sharing Across Private Databases: Secure Union and Intersection Revisited

Abstract—There is a growing,demand,for sharing information across multiple,autonomous,and,private databases. The prob- lem,is usually formulated,as a secure,multiparty,computation problem,where,a,set of parties wish,to jointly compute,a function of their private inputs such that the parties learn only the result of the function,but nothing,else. In this paper,we analyze,existing and,potential solutions for secure,multiparty computation,protocols for union and intersection. We also present an alternative random,shares based approach,and show,that the protocols, although quite simple, are more efficient than existing protocols while providing,reasonable,level of security that can be adjusted,by users. We formally,analyze,the security properties and,the cost of our protocols. We also experimentally,compare the performance,of our approach,with the existing solutions.