SAS

Abstract

The wiretap channel is a setting where one aims to provide information-theoretic privacy of communicated data based solely on the assumption that the channel from sender to adversary is “noisier” than the channel from sender to receiver. The central quest in this area has been secure schemes of optimal rate but decades of work have provided only non constructive proofs of existence of such schemes for a notion of security that from the cryptographic perspective is weak. We define and prove equivalent two strong security metrics, one based on semantic security and the other on entropy. We then provide a new scheme that achieves these strong security goals in polynomial time with optimal rate, thereby not only solving the central open problem in this area but delivering even more in terms of security. This is joint work with Mihir Bellare and Alexander Vardy (UCSD).