# Secure Automatic Identification System (SecAIS): Proof-of-Concept Implementation
###### Abstract  
The automatic identification system (AIS), despite its importance in worldwide navigation at sea, does not provide any defence mechanisms against deliberate misuse, e.g., by sea pirates, terrorists, business adversaries, or smugglers. Previous work has proposed an international maritime identity-based cryptographic infrastructure (mIBC) as the foundation upon which the offer of advanced security capabilities for the conventional AIS can be built. The proposed secure AIS (SecAIS) does not require any modifications to the existing AIS infrastructure, which can still be used for normal operations. Security-enhanced AIS messages enjoying source authentication, encryption, and legitimate pseudo-anonymization can be handled on an as-needed basis. This paper reports on a proof-of-concept implementation of the SecAIS. Specifically, we report on the implementation of the SecAIS over an mIBC founded on the RFC6507 (ECCSI) and the RFC6508 (SAAKE) standards, and we discuss the results of performance tests with this implementation. The tests indicate that the SecAIS is a feasible solution that does not affect the conventional AIS infrastructure and has an affordable operational cost. Automatic Identification System (AIS); e-navigation; maritime security; identity-based encryption/cryptography +
Footnote †: journal: Marine Science and Engineering  
The International Maritime Organization (IMO), [2] in \"Regulation 19\" of the International Convention for the Safety of Life at Sea (SOLAS), Chapter V [3], announced the use of the AIS [4] as an additional navigational system. The International Telecommunications Union (ITU) [5] provided the technical characteristics of the AIS using time division multiple access in the very-high frequency (VHF) maritime mobile band. AIS is a shipborne device that transmits static data (e.g., Maritime Mobile Service Identity (MMSI), IMO number, call sign, ship name, type, vessel's dimensions), dynamic data (e.g., vessel's position (longitude, latitude), speed over ground (SOG), course over ground (COG), navigation status), voyage-related data (e.g., destination, estimated time of arrival, draught), and safety-related data [6]. The MMSI is a nine-digit number that uniquely identifies a vessel. The MMSI is assigned to all the radio communications of that vessel. The International Maritime Organization number (IMO number) is also a distinctive identifier for a vessel and is formed by the prefix \"IMO\" followed by seven digits. The main difference between the IMO number and the MMSI is that the former is the only persistent identifier for a vessel, from the start of its life to the end of it. On the contrary, the MMSI changes when a vessel changes flags and registration authorities. While the accuracy of the data received from the radar is bound by the laws of physics, the accuracy of the data received by AIS devices depends on the trustworthiness of the transmitter. An adversary may transmit fake AIS messages representing fake ships, aids to navigation (AtoN), or search and rescue operations (SARs) [7]. Thus, the radar provides an honest, albeit possibly incomplete, representation of the surroundings of the ship, whilst AIS may give us a deliberately and maliciously distorted representation of it. Furthermore, AIS data are publicly available via specialized internet sites e.g., [[https://www.marinetraffic.com/](https://www.marinetraffic.com/)]([https://www.marinetraffic.com/](https://www.marinetraffic.com/)), accessed on 6 June 2022, that collect forwarded AIS data from all over the world. This unrestricted dissemination of AIS data may come to aid sea pirates and terrorists, and in some cases, it may violate the privacy of passengers [8; 9]. In fact, several incidents involving the AIS have been reported [10; 11; 12].