# Special Issue on Security and Privacy in Blockchains and the IoT Volume II
###### Abstract
[9] analyze the benefits, disadvantages, challenges, and opportunities associated with the use of blockchain-based approaches in this sector. For this purpose, they conducted interviews with ten agribusiness professionals working with blockchain technologies to gain insights into their practical experiences. To this end, they applied a two-phase survey approach, in which the same participants were consulted again two years later, in order to reflect shifts in their assessment. In general, blockchain technologies play an increasingly important role in this application area, especially with regard to governance and information flow within supply chains. However, the findings of the study also clearly reveal that the transition to blockchain-based solutions also entails drawbacks, e.g., high implementation costs. These drawbacks are also critically assessed by the authors. Overall, they come to the conclusion that the benefits and opportunities associated with blockchain application in agribusiness outweigh the challenges and disadvantages. Another application for blockchain technologies is the management of certificates in public key infrastructures (PKIs). In this regard, [PERSON] et al. [10] discuss how DLTs can address the challenges of modern PKIs, namely their heavy focus on a central certificate authority (CA) that manages the root certificates. Since security in PKIs is based on certificate chains, tampering with or blocking access to the root certificate compromises the entire chain and thus renders the PKI useless or inoperable. To this end, the authors therefore propose using a DLT-based data storage. Due to the decentralized nature of DLTs, attackers would only be able to compromise the CA if they had access to all nodes. Furthermore, DLTs establish trust in the authenticity of the certificates provided. The authors additionally adapt the Near-Field Communication Key Exchange scheme, which enables lightweight handling of keys. Evaluation results show that by using blockchain technologies that support smart contracts, the security of the certificates can be increased, but at the expense of performance, e.g., in terms of execution times. The entertainment industry has also realized the potential of blockchain technologies. Digital assets are increasingly distributed as non-fungible tokens (NFTs), which can be verifiably linked to a specific user, e.g., unique player items in a video game, while this can be solved relatively easily from a technical point of view via blockchain entries certifying ownership and authenticity, player perception of such techniques is still largely unresearched. [PERSON] et al. [11] therefore study the opinion of gamers towards the inclusion of such blockchain-based features in games. Based on a game called IkuneRacer, they investigate how players perceive transparency, trust, and user-generated content in blockchain-based games. Their overall research goal is to evaluate whether the implementation of blockchain technologies in games influences player engagement and retention. In this context, it is observed that a combination of asset ownership and user-generated content has a positive effect on the willingness to devote time to a game. With such applications for blockchain technologies, the volume of stored data is increasing, and the underlying data structures are becoming more and more complex. Accordingly, the demand to carry out comprehensive data analytics directly in the blockchain is on the rise as well. In DLTs, however, data access is usually realized via low-level block data instead of high-level data assets, which makes such analytics significantly more difficult. Current blockchain analytics tools address this challenge by using an internal middleware that maps high-level user queries to low-level data interfaces. To improve the analytics capabilities of such tools, [PERSON] et al. [12] introduce an abstraction layer that provides blockchain data in aggregated and pre-processed form to block explorers and other analytics dashboards.