Chapter

Advances in Cryptology - ASIACRYPT 2010

Volume 6477 of the series Lecture Notes in Computer Science pp 195-212

Computationally Secure Pattern Matching in the Presence of Malicious Adversaries

  • Carmit HazayAffiliated withAarhus University
  • , Tomas ToftAffiliated withAarhus University

Abstract

We propose a dedicated protocol for the highly motivated problem of secure two-party pattern matching: Alice holds a text t ∈ {0,1}*. of length n, while Bob has a pattern p ∈ {0,1}*. of length m. The goal is for Bob to learn where his pattern occurs in Alice’s text. Our construction guarantees full simulation in the presence of malicious, polynomial-time adversaries (assuming that ElGamal encryption is semantically secure) and exhibits computation and communication costs of O(n + m) in a constant round complexity.

In addition to the above, we propose a collection of protocols for variations of the secure pattern matching problem: The pattern may contain wildcards (O(nm) communication in O(1) rounds). The matches may be approximated, i.e., Hamming distance less than some threshold ((O(nm) communication in O(1) rounds). The length, m, of Bob’s pattern is secret (O(nm) communication in O(1) rounds). The length, n, of Alice’s text is secret (O(n + m) communication in O(1) rounds).

Keywords

Pattern matching secure two-party computation full simulation malicious adversary