Improving Classical Authentication with Quantum Communication

TL;DR

This paper introduces a quantum-enhanced authentication protocol that improves security over classical methods by leveraging quantum encoding, reducing information leakage, and strengthening key and tag secrecy.

Contribution

It presents a novel quantum protocol for message authentication that surpasses classical schemes in security by using quantum encoding of secret bits.

Findings

Quantum encoding offers more security than classical XOR.

Relationship established between PRG bias and information leakage.

Quantum resources enhance key and tag secrecy.

Abstract

We propose a quantum-enhanced protocol to authenticate classical messages, with improved security with respect to the classical scheme introduced by Brassard in 1983. In that protocol, the shared key is the seed of a pseudo-random generator (PRG) and a hash function is used to create the authentication tag of a public message. We show that a quantum encoding of secret bits offers more security than the classical XOR function introduced by Brassard. Furthermore, we establish the relationship between the bias of a PRG and the amount of information about the key that the attacker can retrieve from a block of authenticated messages. Finally, we prove that quantum resources can improve both the secrecy of the key generated by the PRG and the secrecy of the tag obtained with a hidden hash function.