Quantum Key Distribution Networks Enhance Long-Term Data Security

MULTISS, a new protocol, extends secure long-term data storage across multiple Quantum Key Distribution (QKD) networks. It employs hierarchical secret sharing, enabling secure updates without full reconstruction and demonstrably surpasses the security of the LINCOS protocol, which remains vulnerable to compromise of a single QKD network.

The secure archiving of data for extended periods presents a significant challenge, particularly given the evolving landscape of cyber threats and the limitations of current cryptographic methods. Researchers are increasingly exploring quantum key distribution (QKD) networks as a means to enhance data security, but reliance on a single network introduces vulnerabilities. A new protocol, MULTISS, addresses this by distributing encrypted data across multiple QKD networks, offering resilience against compromise. Thomas Prévost, Olivier Alibart (Université Côte d’Azur / I3S – CNRS) and Anne Marin & Marc Kaplan (VeriQloud) detail their work in the article “MULTISS: un protocole de stockage confidentiel {à} long terme sur plusieurs r{é}seaux QKD”, demonstrating an advancement on existing storage protocols like LINCOS by enabling secret updates without full reconstruction and providing enhanced security against network breaches.

Securing the Future: Mutliss Enables Robust, Distributed Data Storage in the Quantum Era

Quantum computing poses a significant threat to current encryption standards, necessitating the development of quantum-resistant solutions for long-term data security. This work details Mutliss, a protocol designed to provide sustained, secure distributed storage by leveraging multiple Quantum Key Distribution (QKD) networks and a refined implementation of Shamir’s Secret Sharing (SSS). Mutliss addresses the limitations of single-network solutions, such as Lincos, by distributing a secret across geographically diverse QKD infrastructures, bolstering resilience against compromise and ensuring data availability.

Mutliss establishes a viable strategy for sustained, secure distributed data storage anticipating the advent of widespread quantum computing. The protocol integrates Quantum Key Distribution (QKD) with established techniques – Shamir’s Secret Sharing and erasure coding – to construct a resilient system defending against both conventional and quantum-based attacks. By distributing data fragments across multiple, geographically diverse QKD networks, Mutliss enhances availability and mitigates the risk associated with single points of failure or compromise.

The protocol operates by dividing the secret into shares using SSS, but crucially, each share encrypts using a unique key established via a different QKD network. This hierarchical approach significantly enhances resilience; compromising a single QKD network reveals only a portion of the overall secret, preventing complete data exposure. Dynamic share reconstruction allows the system to adapt to network outages or failures, reconstructing the secret from available shares secured by functioning QKD links, ensuring continuous operation. Erasure coding further bolsters data integrity, enabling reconstruction even with lost or corrupted shares, providing an additional layer of protection.

Central to Mutliss’s operation are several key cryptographic concepts that work in concert to deliver robust security. QKD establishes secure key exchange, forming the foundation of the system. Quantum Key Distribution utilises the principles of quantum mechanics to generate and distribute cryptographic keys, guaranteeing detection of any eavesdropping attempts. Shamir’s Secret Sharing divides a secret into multiple parts, requiring a threshold number of shares to reconstruct the original data. Erasure coding introduces redundancy, protecting against data loss. Mutliss builds upon these established techniques, offering a more robust solution than its predecessor, Lincos, which remains vulnerable to compromise if its single QKD network is breached. The protocol also permits secret updates without full reconstruction, improving efficiency and reducing operational overhead.

Mutliss establishes a proactive approach to long-term security, limiting the window of opportunity for potential key compromise. Periodic key refreshment, facilitated by the QKD infrastructure, ensures that even if a key is compromised, the impact is limited in time.

Mutliss offers a valuable contribution to the field of post-quantum cryptography, providing a pathway towards long-term data security in an evolving threat landscape. The protocol’s design prioritises resilience, adaptability, and scalability, making it a viable solution for organisations seeking to protect their data in the quantum era. By leveraging the strengths of QKD, SSS, and erasure coding, Mutliss provides a comprehensive defence against both conventional and quantum-based attacks.

While Mutliss presents a promising advancement, several considerations remain crucial for successful implementation. Implementation complexity is higher than simpler secret sharing schemes, demanding careful management and skilled personnel. Deploying and maintaining multiple QKD networks incurs significant cost, requiring careful planning and resource allocation. The protocol’s performance and scalability with a large number of shares and networks require further investigation, ensuring it can handle real-world data volumes. Furthermore, the trustworthiness of QKD network operators remains a critical assumption, necessitating robust security protocols and vetting procedures.