Practical Post-Quantum Signatures

Denis Butin, Stefan-Lukas Gazdag, Johannes A Buchmann

Attila A. Yavuz, Rouzbeh Behnia

Forward-secure signatures guarantee that the signatures generated before the compromise of private key remain secure, and therefore offer an enhanced compromise-resiliency for real-life applications such as digital forensics, audit logs, and financial systems. However, the vast majority of state-of-the-art forward-secure signatures rely on conventional intractability assumptions and therefore are not secure against quantum computers. Hash-based signatures (HBS) (e.g., XMSS) can offer forward-secure post-quantum security. However, they are efficient only for a pre-defined number of messages to be signed and incur high key generation overhead, highly expensive signing, and large signature sizes for an increasing number of messages. It is an open problem to develop quantum-safe forward-secure signatures that are efficient and practical with a signing capability scalable to their security parameters. In this work, we propose a new series of post-quantum signatures that we call FROG (Forward-secuRe pOst-quantum siGnature). Unlike HBS alternatives, FROG can achieve highly computational efficient signatures with sub-linear key/signature sizes and (practically) unbounded signing capability. This is achieved by transforming suitable post-quantum signatures into forward-secure settings via MMM constructions. We investigated the transformation of prominent post-quantum secure signatures such as Dilithium, WOTS, and BLISS with MMM. Our experiments indicate that FROG outperforms XMSS for the vast majority (if not all for a large number of messages) of performance metrics. We also discuss one-time variants of these base signature schemes that can push the performance of FROG to the edge. Overall, FROG shows a better performance than the existing alternatives with forward-security and therefore is an ideal alternative for the standardization efforts for forward-secure post-quantum signatures.

Maksim Iavich, Nursulu A. Kapalova

Nowadays, quantum computing is developing at an unprecedented speed. This will pose a serious threat to the security of widely used public-key cryptosystems in the near future. Scientists are actively looking for ways to protect against quantum attacks; however, existing solutions still face different limitations in terms of efficiency and practicality. This paper explores hash-based digital signature schemes, post-quantum vector commitments and Verkle tree-based approaches for protecting against quantum attacks. The paper proposes an improved approach to generating digital signatures based on Verkle trees using lattice based vector commitments. In order to further reduce the memory space, the paper offers the methodology of integrating a post-quantum secure pseudo-random number generator into the scheme. Finally, the paper proposes an efficient post-quantum digital signature scheme based on Verkle trees, which minimizes memory requirements and reduces the signature size. Our proposed framework has strong resistance to quantum attacks, as well as high speed and efficiency. This study is an important contribution to the elaboration of post-quantum cryptosystems, which lays the foundation for developing secure and practical digital signature systems in the face of emerging quantum threats.

Charles Bouillaguet, Thibauld Feneuil, Jules Maire +3 more

Kim Tuan Nguyen

In this paper, the authors propose a new type of post–quantum digital signature scheme based on hard problems, which belongs to the group of unsolvable problems that currently have no solution. Therefore, this type of digital signature scheme can be resistant to quantum attacks based on the quantum algorithm proposed by P. Shor. In addition to quantum resistance, the type of signature scheme proposed here can also be used as pre–quantum digital signature schemes that are widely used in current practical applications.