The objective of the proposed research is to measure and secure cyber-physical infrastructures through the maritime domain, focusing on both human and technical dimensions of cybersecurity. This work begins with a systematic study of mariners’ cybersecurity perceptions and practices, revealing how fragmented training and regulatory frameworks shape operational behavior at sea. Building on these insights, the research develops a large-scale measurement framework to detect and characterize GPS spoofing incidents using global Automatic Identification System (AIS) data. By integrating human-centered analysis with data-driven detection methods, the project aims to provide an evidence-based foundation for understanding and mitigating cyber threats in maritime systems and, more broadly, to extend these approaches to other critical infrastructure sectors.