arXiv subjects

Antonia Tsili

Publications and source records attributed to Antonia Tsili.

3 recordsLinked to original sources

arXiv2026

A Scalable Cloud-Orchestrated and Service-Oriented Multi-Domain QKD Network with PQC Integration

Quantum key distribution (QKD) offers unconditional security but existing QKD networks remain difficult to scale across heterogeneous infrastructures and administrative domains due to vendor-specific interfaces, trusted-node constraints, and limited interoperability. This work presents a flexible multi-domain and multi-site quantum-secure network architecture integrating vendor-agnostic QKD, SDN orchestration, and cloud-managed trust services. Communication is based on Zero Trust Network Access protocols featuring multi-level authentication mechanisms building upon post-quantum cryptography (PQC) signature and key encapsulation algorithms. The system is deployed on a real-world testbed with domains incorporating QKD nodes from 3 vendors, as well as domains without QKD infrastructure elements. Experimental results show that PQC and SDN overhead remain relatively low even on constrained devices, with the main bottleneck being QKD key retrieval and vendor-specific key streaming limitations. The proposed framework extends quantum-safe key transport beyond native QKD boundaries while preserving flexibility, interoperability, and compatibility with existing infrastructures.

cs.CR↗

arXiv2025

A Scalable Framework for Post-Quantum Authentication in Public Key Infrastructures

This work explores the performance and scalability of a hierarchical certificate authority framework with automated certificate issuance employing post-quantum cryptographic (PQC) signature algorithms. The system is designed for compatibility with both classical and PQC algorithms, promoting crypto-agility while ensuring robust security against quantum-based threats. The proposed framework design expects minimal cryptographic requirements from potential clients, protects certificates of high importance against cross-dependent chains-of-trust and allows for prompt switching between classical and PQC algorithms. Finally, we evaluate SPHINCS$^+$, Falcon, and Dilithium variants in various configurations of certificate issuance and verification accommodating a large client base, underlining the trade-offs in balancing performance, scalability, and security.

cs.CR↗

arXiv2023

First Order Methods for Geometric Optimization of Crystal Structures

The geometric optimization of crystal structures is a procedure widely used in Chemistry that changes the geometrical placement of the particles inside a structure. It is called structural relaxation and constitutes a local minimization problem with a non-convex objective function whose domain complexity increases according to the number of particles involved. In this work we study the performance of the two most popular first order optimization methods in structural relaxation. Although frequently employed, there is a lack of their study in this context from an algorithmic point of view. We run each algorithm in combination with a constant step size, which provides a benchmark for the methods' analysis and direct comparison. We also design dynamic step size rules and study how these improve the two algorithms' performance. Our results show that there is a trade-off between convergence rate and the possibility of an experiment to succeed, hence we construct a function to assign utility to each method based on our respective preference. The function is built according to a recently introduced model of preference indication concerning algorithms with deadline and their run time. Finally, building on all our insights from the experimental results, we provide algorithmic recipes that best correspond to each of the presented preferences and select one recipe as the optimal for equally weighted preferences. Alongside our results we present our open source Python software veltiCRYS, which was used to perform the geometric optimization experiments. Our implementation, can be easily edited to accommodate other energy functions and is especially targeted for testing different methods in structural relaxation.

math.OC↗