Non-Malleable Codes from the Wire-Tap Channel

TL;DR

This paper establishes a connection between the wire-tap channel and non-malleable codes, presenting a new, more efficient construction for certain classes of modifications using coset-coding.

Contribution

It introduces a novel construction of non-malleable codes based on the wire-tap channel, simplifying and improving upon previous methods.

Findings

New construction for NMC using wire-tap channel techniques

More efficient and easier to implement than previous schemes

Applicable to a subset of bit-wise independent functions

Abstract

Recently, Dziembowski et al. introduced the notion of non-malleable codes (NMC), inspired from the notion of non-malleability in cryptography and the work of Gennaro et al. in 2004 on tamper proof security. Informally, when using NMC, if an attacker modifies a codeword, decoding this modified codeword will return either the original message or a completely unrelated value. The definition of NMC is related to a family of modifications authorized to the attacker. In their paper, Dziembowski et al. propose a construction valid for the family of all bit-wise independent functions. In this article, we study the link between the second version of the Wire-Tap (WT) Channel, introduced by Ozarow and Wyner in 1984, and NMC. Using coset-coding, we describe a new construction for NMC w.r.t. a subset of the family of bit-wise independent functions. Our scheme is easier to build and more efficient than the one proposed by Dziembowski et al.