Automatic Identification System (AIS) is a maritime radio broadcast system used by ships and nearby stations to share vessel identity, position, course, speed, and related navigation data. It improves situational awareness at sea by letting crews, port operators, and monitoring systems see traffic without relying only on visual observation.
From a cyber security perspective, AIS matters because it is a broadcast medium: receivers can hear the data, but the protocol does not guarantee that every message is truthful or complete. That makes AIS useful for tracking and alerting, but also vulnerable to spoofed, replayed, missing, or malformed messages. Defenders and analysts therefore treat AIS as helpful telemetry, not absolute ground truth, and they correlate it with radar, charts, logs, and other sensors. Any software that decodes AIS should also validate input carefully, because external data can be corrupted or intentionally misleading.