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，量子计算日益成为现实，带来了若干网络安全挑战。现代密码学建立在特定数学问题计算复杂性的基础上，但随着新型量子计算机的出现，经典方法可能不足以保障通信安全。本文通过分析伽利略开放服务导航消息认证（OSNMA）的现状以应对这些新型威胁。该分析评估基于OSNMA技术文档，审阅了参与美国国家标准与技术研究院（NIST）标准化流程的后量子密码学（PQC）算法，并研究了其在伽利略服务中实现的可能性。采用PQC方法的主要障碍在于签名和密钥的尺寸问题。分析表明OSNMA尚未做好应对量子威胁的准备，需要进行重大变革。本研究最后评估了可在短期内实施以维持系统完整性的不同临时防护措施。