Non-committing encryptions based on oblivious Naor-Pinkas cryptosystems

Abstract

Designing non-committing encryptions tolerating adaptive adversaries, who are able to corrupt parties on the fly in the course of computation has been a challenge task. In this paper, we make progress in this area. First, we introduce a new notion called oblivious Naor-Pinkas cryptosystems that benefits us to extract the randomness used to generate local public keys and thus enable us to construct corresponding simulator for a given adaptive adversary in a real-world protocol. We then give a simple construction of non-committing encryptions based on oblivious Naor-Pinkas cryptosystems. We show that the proposed non-committing encryption scheme is provably secure against an adaptive PPT adversary assuming that the decisional Diffie-Hellman problem is hard. © 2009 Springer-Verlag.