Before revision: The encoded AIS data, using AIS-ASCII6 0* End of data, number of unused bits at end of encoded data (0-5) 7D NMEA checksum (NMEA 0183 Standard CRC16) Security AIS was designed as an intentionally open standard and due to the unauthenticated and unencrypted nature of AIS, recently Balduzzi, Pasta, Wilhoit et al.showed that AIS is vulnerable to different threats like use is mandated for class-A vessels and widely used by class-B vessels, so it must be transmitted in an open-source system on marine designated radio channels.Lázaro, F.; Raulefs, R.; Bartz, H.; Jerkovits, T. (September 2021).
After revision: The encoded AIS data, using AIS-ASCII6 0* End of data, number of unused bits at end of encoded data (0-5) 7D NMEA checksum (NMEA 0183 Standard CRC16) Security AIS use is mandated for class-A vessels and widely used by class-B vessels, so it must be transmitted in an open-source system on marine designated radio channels.Lázaro, F.; Raulefs, R.; Bartz, H.; Jerkovits, T. (September 2021).