METHOD FOR SELECTIVELY ENCRYPTING DATA TRANSMITTED TO AND REBROADCAST BY SATELLITE

摘要

AIS (Automatic Identification System) is a system of communication between vessels, for example fishing vessels, which makes it possible to limit the collisions between these vessels and which allows a surveillance of the maritime traffic for the coast thanks to coastal stations which listen to the communications. The satellite collection of this data allows maritime surveillance far from the coast and verification of the data transmitted by the analysis of the received signal. The maritime surveillance authorities do not want the data concerning, for example, the position of ships in their territorial waters, collected by satellite, to be disseminated globally. Indeed, this would allow a user, by listening to the satellite to know the AIS messages exchanged far from these coasts. The AIS messages contain the position of the transmitting vessel, as well as its identifier, its direction, etc. The invention consists in setting up an encryption of the descended data based on the content of these data. Data encryption also allows authorities to provide AIS data as a possibly paid service.