Abstract

As quantum computing advances, public-key cryptographic algorithms risk becoming obsolete, requiring the development and implementation of quantum-resistant alternatives. This thesis evaluates SPHINCS+, a stateless hash-based digital signature scheme recently standardized by NIST under the FIPS 205 standard named Stateless Hash-Based Digital Signature Algorithm (SLH-DSA), which was selected for being a conservative and robust choice due to its reliance solely on well-understood cryptographic primitives. In the context of the growing need for quantum-resistant cryptographic solutions, determining the readiness of SPHINCS+ involves assessing its practical viability across different application domains and evaluating how well it meets today’s and future needs. To achieve this, we analyze SPHINCS+ in the following areas. Our analysis begins by benchmarking SPHINCS+ against classical and post-quantum signature schemes such as the Elliptic Curve Digital Signature Algorithm (ECDSA) and ML-DSA, measuring key generation, signing, and verification times, as well as signature sizes across multiple variants. The scheme’s performance is evaluated in constrained environments such as Vehicle-to-Vehicle (V2V) communication, simulating its integration into mock blockchain transactions and TLS-like protocols to assess feasibility and scalability. In addition, this work investigates hybrid cryptographic models that combine SPHINCS+ with classical schemes to ensure backward compatibility and cryptographic agility, as a transitional solution during this post-quantum migration period. The findings suggest that, while SPHINCS+ offers strong security against quantum computers and has been standardized by NIST, its substantial performance drawbacks raise critical concerns about its practicality. These limitations indicate that SPHINCS+, despite its conservative design, may not be suitable for many real-world applications. As such, we believe it is imperative that an alternative signature scheme be developed and standardized alongside the current selection to ensure feasibility across all types of applications.

Library of Congress Subject Headings

Quantum computing--Security measures; Cryptography; Hashing (Computer science)

Publication Date

6-2025

Document Type

Thesis

Student Type

Graduate

Degree Name

Computer Science (MS)

Department, Program, or Center

Computer Science, Department of

College

Golisano College of Computing and Information Sciences

Advisor

T.J. Borrelli

Advisor/Committee Member

Stanislaw Radziszowski

Advisor/Committee Member

Richard Lange

Campus

RIT – Main Campus

Plan Codes

COMPSCI-MS

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