Efficient Protocols for Set Intersection and Pattern Matching with Security Against Malicious and Covert Adversaries

In this paper we construct efficient secure protocols for

set intersection

and

pattern matching

. Our protocols for securely computing the set intersection functionality are based on secure pseudorandom function evaluations, in contrast to previous protocols that used secure polynomial evaluation. In addition to the above, we also use secure pseudorandom function evaluation in order to achieve secure pattern matching. In this case, we utilize specific properties of the Naor-Reingold pseudorandom function in order to achieve high efficiency.

Our results are presented in two adversary models. Our protocol for secure pattern matching and one of our protocols for set intersection achieve security against

malicious adversaries

under a relaxed definition where one corruption case is simulatable and for the other only privacy (formalized through indistinguishability) is guaranteed. We also present a protocol for set intersection that is fully simulatable in the model of covert adversaries. Loosely speaking, this means that a malicious adversary can cheat, but will then be caught with good probability.