Quantum computing becomes more of a reality as time passes, bringing several cybersecurity challenges. Modern cryptography is based on the computational complexity of specific mathematical problems, but as new quantum-based computers appear, classical methods might not be enough to secure communications. In this paper, we analyse the state of the Galileo Open Service Navigation Message Authentication (OSNMA) to overcome these new threats. This analysis and its assessment have been performed using OSNMA documentation, reviewing the available Post Quantum Cryptography (PQC) algorithms competing in the National Institute of Standards and Technology (NIST) standardization process, and studying the possibility of its implementation in the Galileo service. The main barrier to adopting the PQC approach is the size of both the signature and the key. The analysis shows that OSNMA is not yet prepared to face the quantum threat, and a significant change would be required. This work concludes by assessing different temporal countermeasures that can be implemented to sustain the system's integrity in the short term.

翻译：随着时间推移，量子计算正逐步成为现实，带来了诸多网络安全挑战。现代密码学基于特定数学问题的计算复杂性，但随着新型量子计算机的出现，传统方法可能不足以保障通信安全。本文分析了伽利略开放服务导航电文认证（OSNMA）的现状，以应对这些新威胁。该分析及评估基于OSNMA文献，通过审查美国国家标准与技术研究院（NIST）标准化进程中参与竞争的后量子密码学（PQC）算法，并研究其在伽利略服务中实施的可能性。采用PQC方法的主要障碍在于签名和密钥的尺寸。分析表明，OSNMA尚未具备应对量子威胁的能力，需进行重大变革。本研究最终评估了多种可在短期内实施以维护系统完整性的时间对策。