Abstract
Maritime shipping is currently undergoing rapid digitalization, but with increasing exposure to cyber threats, there is a need to improve the security of the ship communication technology used during operations across international waters, as well as close to local shores and in ports. To this aid, there are ongoing standardization efforts for an international maritime Public Key Infrastructure, but the inherent properties of limited connectivity and bandwidth make certificate revocation a problematic affair compared to traditional Internet systems. The main contribution of this paper is an analysis of certificate revocation techniques based on how they fulfil fundamental maritime requirements and simulated usage over time. Our results identify CRLs (with Delta CRLs) and CRLite as the two most promising candidates. Finally, we outline the pros and cons with these two different solutions.