We propose a protocol for secure mining of association rules in horizontally distributed s. The current leading

protocol is that of Kantarcioglu and Clifton [18]. Our protocol, like theirs, is based on the Fast Distributed Mining (FDM) algorithm of

Cheung et al. [8], which is an unsecured distributed version of the Apriori algorithm. The main ingredients in our protocol are two novel

secure multi-party algorithms—one that computes the union of private subsets that each of the interacting players hold, and another

that tests the inclusion of an element held by one player in a subset held by another. Our protocol offers enhanced privacy with respect

to the protocol in [18]. In addition, it is simpler and is significantly more efficient in terms of communication rounds, communication cost

and computational cost.