# Using Blockchain for Data Collection in the Automotive Industry Sector: A Literature Review
## 4 Discussion  
The purpose of the current study was to conduct a review of published articles that describe the challenges of using blockchain technology for data collection in the automotive industry. Accordingly, this review investigated gaps in the proposed solutions for data collection. In addition, it offers practical suggestions to improve the data-collection process, taking into account the unique requirements and experiences of automotive industry stockholders. The following trends emerged: using mass messages to ensure good latency, changing public keys for driver anonymity, adapting security systems against security attacks, analyzing blockchain costs to know the feasibility of a solution, offering different uses in production and services for the automotive industry, and using segmental data collection to make the process more scalable and usable in a real context with large networks. Connectivity is one of the most important challenges for data collection, because vehicles are fast objects and are not guaranteed to always be strongly connected to the Internet. This review showed that the selected articles proposed several solutions to this problem; these solutions combine the connection via the 3G/4G/5G mobile network and Wi-Fi with the possibility of short-time local data storing and guarantee quality and reliability of data sharing. However, future research could focus more on using public Wi-Fi networks or using connections from other cars as another possible solution for uploading data to the blockchain. Although it is proven that the use of bulk messages to shorten the time of loading and processing of data in the blockchain is an effective, secure solution and could be tested in a real-world example, only one article introduced a solution to ensure good connectivity and latency by this method. This review showed that, although researchers have focused on solutions that preserve privacy in blockchain data collection, few have considered the GDPR; for example, only one article proposed a solution that allows the right to rectification and the right to be forgotten. However, the importance of compliance with all data-collection laws seems obvious, as vehicle data are collected worldwide. In addition, it is necessary to focus more on solutions that allow for data deletion when requested by the driver, especially as blockchain is built as an immutable solution. Security attacks, which are the main challenge for data collection, should be studied in their entirety, as in Reference [10]. More specifically, researchers should classify attacks and carry out more tests and simulations for possible attacks (i.e., DDoS, MITM, collusion, and data exposure). This will improve integrity and provide a secure basis for the future expansion of data extraction. Moreover, if all types of attacks on large car networks are not avoided, conflicts and threats to traffic flow can be generated. In addition, insurance companies would also be affected and could allow fraud if the data were not verified biometrically. However, further work on possible anti-attack methods is needed. This review revealed that nine of the thirteen proposed solutions have performed performance tests. The test results proved that blockchain technology could be used for data collection in the automotive industry. However, four articles [4, 11, 12, 13] did not perform any tests or simulations to verify their solutions. Therefore, these solutions should be tested in simulations to ensure that they are usable. In addition, the other proposed solutions can be moved to the small-scale testing phase in the real world. Scalability is a key factor in achieving sustainability in the automotive industry. In addition, potentially large vehicle networks must be scalable, as the number of connected vehicles increases. However, it still implies a limitation in the data-collection research area, because scalability has not been widely researched in the selected articles.