# Decentralized Documentation of Maritime Traffic Incidents to Support Conflict Resolution
## 5 Application and Evaluation
### Discussion
The Voyage Data Recorder can record various information in an automated way but is mainly limited to information about its own ship. However, due to its robustness and certification, the data is kept very secure, making it difficult to manipulate it [47]. In addition, the data is stored directly on the ship, so it does not need to be migrated to an external infrastructure. However, as mentioned above, retrieving the data turns out to be time-consuming, which is why the approach is not used in practice to clarify minor incidents [4]. A connection to the Internet is not required. The most important events on board are documented in a logbook [3]. In general, this is a manual process that is still carried out by hand. Accordingly, a logbook does not record detailed data. In addition, it is only expected that the logbook will be filled out truthfully [48]. Therefore, it can be comparatively easily manipulated. However, on the positive side, the data records are only stored on the vessel itself, and the effort for the documentation and readout is low. The logbook also does not require an internet connection. The blockchain and TSA-based approaches differ from the classic approaches. Both approaches are, in principle, data-independent so that any data can be documented. By storing a hash on a blockchain or signing the hash with a TSA, subsequent changes to the data can be easily identified. In both cases, the data is communicated externally, but since the data is only transmitted as a hash, no conclusions can be drawn about the original data (cf. Section 4). The complexity of the blockchain solution depends very much on how the blockchain itself is designed. Accordingly, the effort required to enter and verify a hash can be very high. However, since each TSA follows a standardized process and the data is cryptographically signed, the integrity of the data can be verified by examining the signature in a computationally efficient way and without a network of multiple blockchain nodes. Therefore, the overall complexity of the approach can be considered lower than the blockchain-based solution. However, both approaches require an internet connection in order to document the data in a tamper-proof way. In the near future, it is expected that ships will also have a permanent connection via satellites [49; 50; 51]. In regions close to land, most ships already have an LTE connection. Therefore, this criterion should not be a major limitation in the future. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Approach** & \begin{tabular}{c} **Variety of** \\ **Data** \\ \end{tabular} & \
\begin{tabular}{c} **Tamper-** \\ **Proof** \\ \end{tabular} &
\begin{tabular}{c} **Data** \\ **Sovereighty** \\ \end{tabular} & **Complexity** & **Connectivity** \\ \hline Voyage Data Recorder & o & + & + & - & + \\ Logbook & - & - & + & + & + \\ Blockchain-based approach & + & + & + & - & - \\ TSA-based approach & + & + & + & o & - \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparison of different approaches for the reconstruction of maritime situations (+: fulfilled; o: partially fulfilled; -: not fulfilled). Overall, the existing approaches for documenting traffic situations focus on data from the own vessel. Other external data sources are not part of the documentation. Nevertheless, the data from other sources could contribute to a better understanding of the cause of critical traffic situations. Therefore, establishing such a system in the maritime domain would make sense. In principle, the blockchain-based and TSA-based approaches are suitable for tamper-proof documentation. However, the complexity of a TSA-based approach will usually be lower, so it should be preferred.