Hash-then-Encode: A Modular Semantically Secure Wiretap Code

摘要

We propose a modular construction of a semantically secure wiretap code that achieves secrecy capacity for a large class of wiretap channels. Security of the construction is proved by interpreting the construction as an instance of an invertible extractor, and use the framework in Bellare et al. [1] to complete the proof. The construction has computation for encoding and decoding equivalent to hashing, and the smallest effective transmission rate among known modular capacity achieving constructions. We also give a modular construction of invertible Universal Hash Functions (UHF) from an XOR Universal Hash Functions that is of independent interest.