Automata Evaluation and 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 P1 holds a pattern and party P2 holds a text. The goal of P1 is to learn where the pattern appears in the text, without revealing it to P2 or learning anything else about P2'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 P1 holds an automaton and party P2 holds an input string, and they need to decide if the automaton accepts the input, without learning anything else.