Noise-Tolerant Quantum Tokens for MAC

TL;DR

This paper introduces the first noise-tolerant quantum tokenized MAC scheme based on BB84 states, enhancing practicality and security in quantum cryptography with up to 14% noise tolerance.

Contribution

It presents a simple, noise-tolerant quantum TMAC construction using BB84 states, improving feasibility over previous schemes.

Findings

First noise-tolerant TMAC construction with 14% noise tolerance

Elementary construction based on BB84 states

Achieves existential unforgeability assuming post-quantum one-way functions

Abstract

Message Authentication Code or MAC, is a well-studied cryptographic primitive that is used in order to authenticate communication between two parties sharing a secret key. A Tokenized MAC or TMAC is a related cryptographic primitive, introduced by Ben-David & Sattath (QCrypt'17) which allows limited signing authority to be delegated to third parties via the use of single-use quantum signing tokens. These tokens can be issued using the secret key, such that each token can be used to sign at most one document. We provide an elementary construction for TMAC based on BB84 states. Our construction can tolerate up to 14% noise, making it the first noise-tolerant TMAC construction. The simplicity of the quantum states required for our construction combined with its noise tolerance, makes it practically more feasible than the previous TMAC construction. The TMAC is existentially unforgeable against adversaries with signing and verification oracles (i.e., analogous to EUF-CMA security for MAC), assuming post-quantum one-way functions exist.