# Decentralized Documentation of Maritime Traffic Incidents to Support Conflict Resolution
## 6 Summary and Conclusions  
In this paper, we have presented an approach for the creation of a decentralized and trustworthy documentation of maritime traffic situations. Our research literature reveals that the clarification of minor traffic incidents presents a particular difficulty, since the VDR on board a vessel is often only read by the authorities in the case of major incidents. A forgery-proof data basis is generally not available for clarification of smaller incidents. Furthermore, apart from ship-related data, e.g., the VDR, and a lot of contextual information such as weather information, is recorded by other entities. This contextual information can be very important for a proper documentation of an incident but is currently not addressed by existing approaches. Therefore, we have taken up this challenge and by first analyzing which methods already exist to persist data in a tamper-proof way. Besides central authorities that perform the documentation and blockchain-based approaches, timestamping authorities that have the task of adding a timestamp to data in a cryptographically verifiable way can also be utilized. Compared to the other approaches, TSAs have the advantage of being able to certify the integrity of data records using standardized and computationally efficient operations. However, as the maritime domain is an international industry with many different participants from a large number of countries, it is unrealistic to assume that all participants will agree on a single central TSA. For the agreement on a TSA, the Negotiation Protocol was introduced, which ensures that a TSA with the maximum trust will be found among the participants. For communication, a P2P network is established when a document worthy situation is initiated. The presented approach also allows storing data records on the documenting party's infrastructure. In this way, the participants retain complete control over their own data. Only in the case of a conflict resolution, the participant needs to share his certified data with the other parties. To demonstrate the functionality of the approach, we integrated our implementation into the infrastructure of the SmartKai Testbed in Cuxhaven. The approach was successfully tested based on a berthing maneuver involving three different parties. It was shown that even in real deployment environments, the parties could communicate over the dynamically created P2P network to agree along the Negotiation Protocol on a common TSA, to certify their own data using the authority and persist it in a local database. Nevertheless, it should be noted that the presented approach also has some limitations. For example, a continuous internet connection or additional effort to establish non-IP-based communication to a gateway is required to agree on a TSA and to send the data recordings to the TSA for certification. Especially when the approach should be used on the open sea, where ships usually have limited or no internet connection, this could cause problems. Still, by using alternative communication channels such as the VHF Data Exchange System (VDES), or by caching the required information beforehand, it would be possible to exchange the required information even without a stable internet connection. A further limitation is that only parties that already have the required software installed on their infrastructure can participate in the documentation process. Parties that do not have the software or hardware can not be included in the documentation process. Lastly, the presented approach only grants that the data already existed on the date issued by the TSA. However, the data could have been manipulated before it was signed by the provider. Therefore, it is extremely important to look at data from multiple participants when resolving conflicts and see if they match. In future work, we envision being able to ensure that a participant's data records have not been manipulated before the time of certification.