arXiv subjects

Daniel Herzinger

Publications and source records attributed to Daniel Herzinger.

4 recordsLinked to original sources

arXiv2025

Time-Based State-Management of Hash-Based Signature CAs for VPN-Authentication

Advances in quantum computing necessitate migrating the entire technology stack to post-quantum cryptography. This includes IPsec-based VPN connection authentication. Although there is an RFC draft for post-quantum authentication in this setting, the draft does not consider (stateful) hash-based signatures despite their small signature size and trusted long-term security. We propose a design with time-based state-management that assigns VPN devices a certificate authority (CA) based on the hash-based signature scheme XMSS. The CA then issues leaf certificates which are based on classical cryptography but have a short validity time, e. g., four hours. It is to be expected that even large quantum computers will take significantly longer to break the cryptography, making the design quantum-secure. We propose strategies to make the timekeeping more resilient to faults and tampering, as well as strategies to recognize a wrong system time, minimize its potential damage, and quickly recover. The result is an OpenBSD implementation of a quantum-safe and, regarding the leaf certificates, highly flexible VPN authentication design that requires significantly less bandwidth and computational resources compared to existing alternatives.

cs.CR↗

arXiv2025

On the Formalization of Cryptographic Migration

We present a novel approach to gaining insight into the structure of cryptographic migration problems which are classic problems in applied cryptography. We use a formal model to capture the inherent dependencies and complexities of such transitions. Using classical mathematical results from combinatorics, probability theory, and combinatorial analysis, we evaluate the challenges of migrating large cryptographic IT infrastructures and prove that - in a suitable sense - cryptographic migration exhibits a certain expected complexity. We also provide numerical data for selected parameter sets. Furthermore, we analyze the proposed model in terms of real-world patterns and its practical applicability. Additionally, we discuss the challenges of modeling real-world migration projects. As concrete examples we examine the transition to post-quantum cryptography of the CI/CD system GitLab and the multi-level technological transition of distribution power grids. This work paves the way for future advancements in both the theoretical understanding and practical implementation of cryptographic migration strategies.

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arXiv2024

Toward a Common Understanding of Cryptographic Agility -- A Systematic Review

Cryptographic agility is gaining attention due to its crucial role in maintaining cryptographic security in a rapidly evolving technological landscape. However, despite its increasing importance, the term cryptographic agility remains vaguely defined and there is no clear consensus on its exact meaning. This lack of clarity poses a challenge since the need for agility becomes more urgent as new cryptographic vulnerabilities and advanced computing threats emerge, emphasizing the need for a systematic approach to clarify and refine the notion on cryptographic agility. In this paper, we systematize the concept of cryptographic agility by providing three research contributions. First, we review current definitions across academic and gray literature, identifying six distinct categories to differentiate every aspect within the definitions. Second, we synthesize these insights to establish a comprehensive, canonical definition of cryptographic agility. Third, we explore the relationship between cryptographic agility and the related concepts cryptographic versatility and interoperability. In our discussion, we examine the relevance of cryptographic agility, highlight its trade-offs with complexity, assess its individual applicability, and illustrate its various contexts by offering an additional application-specific definition. Our work provides a new perspective on cryptographic agility and related concepts, based on systematical research to clarify and enhance its future use.

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arXiv2024

Migrating Software Systems towards Post-Quantum-Cryptography -- A Systematic Literature Review

Networks such as the Internet are essential for our connected world. Quantum computing poses a threat to this heterogeneous infrastructure since it threatens fundamental security mechanisms. Therefore, a migration to post-quantum-cryptography (PQC) is necessary for networks and their components. At the moment, there is little knowledge on how such migrations should be structured and implemented in practice. Our systematic literature review addresses migration approaches for IP networks towards PQC. It surveys papers about the migration process and exemplary real-world software system migrations. On the process side, we found that terminology, migration steps, and roles are not defined precisely or consistently across the literature. Still, we identified four major phases and appropriate substeps which we matched with also emerging archetypes of roles. In terms of real-world migrations, we see that reports used several different PQC implementations and hybrid solutions for migrations of systems belonging to a wide range of system types. Across all papers we noticed three major challenges for adopters: missing experience of PQC and a high realization effort, concerns about the security of the upcoming system, and finally, high complexity. Our findings indicate that recent standardization efforts already push quantum-safe networking forward. However, the literature is still not in consensus about definitions and best practices. Implementations are mostly experimental and not necessarily practical, leading to an overall chaotic situation. To better grasp this fast moving field of (applied) research, our systematic literature review provides a comprehensive overview of its current state and serves as a starting point for delving into the matter of PQC migration.

cs.CR↗