Assessing trust for determining the reliability of information

This chapter explores methods for determining the reliability of Automated Identification System (AIS) messages. The primary use of AIS messages in the naval domain is to avoid collisions, therefore they contain kinematic information about ships. Moreover, AIS messages contain information like the ship name and its identifiers, so AIS messages can be used to identify ships. However, since the information contained in these messages is not necessarily correct (because, for instance, a malicious sender might want to declare a different identity than its own), in order to properly use them, we should assess their trust level. In general, trust is an important concept that helps to take decisions when the available information is limited or contradicting. In the case of AIS messages, this might occur when only few messages about a given ship are available or when messages conflict either against themselves or against other sources like Web sites reporting ship information. We describe ongoing work about the quantification of trust assessments in AIS messages, by means of statistical and logical analysis and by enriching AIS messages with information obtained from the Web.