Secure extended wildcard pattern matching protocol from cut-and-choose oblivious transfer

Abstract

Secure two-party pattern matching involves two parties, where a server owns the long text and a client has the pattern. The goal is for the client to learn the positions in which his pattern appears in the text, while leaking nothing to the server. In secure wildcard pattern matching (WPM), wildcards that can match any character arbitrarily are allowed in the pattern of the client.In this study, we first propose an extended variant of the standard WPM functionality, which we termed extended wildcard pattern matching (EWPM). The EWPM functionality allows the client to acquire the entire set of substrings that match his pattern, rather than the corresponding locations. We constructed a secure protocol of the EWPM functionality using cut-and-choose oblivious transfer (CCOT) in a semi-honest model. The efficiency of the proposed protocol approximates that of the state-of-the-art scheme. Furthermore, we implemented our protocol to demonstrate its actual practicality. The experimental result shows that when the pattern length is 210 and the text length is less than 220, the total execution time is less than 2 s.