Generalized Quantum-assisted Digital Signature

TL;DR

This paper presents GQaDS, an enhanced quantum-assisted digital signature scheme that improves security and reduces signature length by integrating Carter-Wegman MACs and optimizing parameters for specific scenarios.

Contribution

It introduces GQaDS with strengthened security, reduced signature length, and a simplified deterministic version for trusted second verifiers, advancing quantum digital signature methods.

Findings

Security against forgery is rigorously analyzed and optimized.

Signature length is significantly reduced through new cryptographic techniques.

A simplified deterministic scheme is proposed for trusted verifier scenarios.

Abstract

This paper introduces Generalized Quantum-assisted Digital Signature (GQaDS), an improved version of a recently proposed scheme whose information theoretic security is inherited by adopting QKD keys for digital signature purposes. Its security against forging is computed considering a trial-and-error approach taken by the malicious forger and GQaDS parameters are optimized via an analytical approach balancing between forgery and repudiation probabilities. The hash functions of the previous implementation are replaced with Carter-Wegman Message Authentication Codes (MACs), strengthening the scheme security and reducing the signature length. For particular scenarios where the second verifier has a safe reputation, a simplified version of GQaDS, namely deterministic GQaDS, can further reduce the required signature length, keeping the desired security strength.