Text Search Protocols with Simulation Based Security

This paper presents an efficient protocol for securely computing the fundamental problem of pattern matching. This problem is defined in the two-party setting, where party P 1 holds a pattern and party P 2 holds a text. The goal of P 1 is to learn where the pattern appears in the text, without revealing it to P 2 or learning anything else about P 2's text. Our protocol is the first to address this problem with full security in the face of malicious adversaries. The construction is based on a novel protocol for secure oblivious automata evaluation which is of independent interest. In this problem party P 1 holds an automaton and party P 2 holds an input string, and they need to decide if the automaton accepts the input, without learning anything else.