Composable, Unconditionally Secure Message Authentication without any Secret Key

TL;DR

This paper presents a method for message authentication that is unconditionally secure and does not require a secret key, leveraging channel noise differences to ensure error correction and authentication simultaneously.

Contribution

It introduces a novel encoding and decoding scheme that achieves secure message authentication without secret keys, suitable for composable systems.

Findings

Achieves error correction and authentication simultaneously

Provides information-theoretic security without secret keys

Can be integrated with other protocols securely

Abstract

We consider a setup in which the channel from Alice to Bob is less noisy than the channel from Eve to Bob. We show that there exist encoding and decoding which accomplish error correction and authentication simultaneously; that is, Bob is able to correctly decode a message coming from Alice and reject a message coming from Eve with high probability. The system does not require any secret key shared between Alice and Bob, provides information theoretic security, and can safely be composed with other protocols in an arbitrary context.