# Special Issue on Security and Privacy in Blockchains and the IoT Volume II
###### Abstract
The work aims to improve the auditability and intuitiveness of DLTs by providing users with lightweight data interfaces such as dashboards. The benefits of the proposed abstraction layer architecture are illustrated by means of an industrial case study. Similar to IoT-based applications, the extensive accumulation of data from a wide range of domains raises confidentiality and privacy concerns in the context of blockchain as well. For this purpose, [PERSON] et al. [13] consider the data collected using 3D sensing technology. Such sensors create point clouds, i.e., annotated geometric information which is arranged in a 3D space. This technology is used, for instance, in autonomous driving. In such a use case, the data are always related to a driver in one way or another, so special attention must be paid to data security, e.g., in terms of access, processing, and sharing. To this end, the authors present SAUSA, an approach that combines blockchain technologies with concepts of software-defined networking (SDN). SAUSA monitors and controls any kind of interaction with the point cloud data. Using a hybrid on-chain/off-chain storage strategy, less sensitive metadata can be stored in a distributed data store, whereas sensitive payloaddata can reside on a private storage. This way, SAUSA enables efficient and resilient point cloud applications while still giving users full control over their data. Such an approach is suitable whenever it is possible to share no or very little data with certain parties. In the context of elections, however, this is not possible as the election results have to be verifiable, i.e., it must be ensured that no votes are cast illegitimately and that every legitimate vote is counted. Notwithstanding, privacy has a high priority with regard to elections as well since it must be ensured that a vote can be cast confidentially and that it cannot be traced back to the voter. [PERSON] et al. [PERSON] et al. (2014) address this paradox by leveraging blockchain technologies. In their proposed PVPBC e-voting system, a permissioned distributed ledger and smart contracts are applied, achieving effective authorization while preserving revocable anonymity properties. The adopted Selene voting scheme ensures that voters can easily verify that their votes are accurately captured by the system, without having to deal with the underlying cryptographic complexity. This way, not only the most crucial security requirements for e-voting systems are addressed--e.g., fairness, verifiability, and privacy--but experimental results also demonstrate that PVPBC is highly scalable. In the final research article, the two thematic blocks of this Special Issue--namely, IoT and blockchain technology--are brought together. In this paper, [PERSON] et al. [PERSON] et al. (2015) discuss next-generation networks, which aim to provide features such as ultra-low latency, high availability, and wide service coverage to users. This is achieved by the integration of SDN and network function virtualization. To improve elasticity and dynamics and reduce the necessity for human interaction, the Zero-touch Service Management (ZSM) framework can achieve complete end-to-end automation of network service management, even across different domains. However, this raises security concerns. The authors argue that the use of blockchain technology in a trustless environment such as the ZSM can create inherent security in terms of data integrity and transaction validity. For this reason, they introduce an architecture for multi-domain network infrastructures that are managed via ZSM, yet the management functions are implemented as smart contracts. The authors discuss different blockchain systems that are suitable for this purpose and provide implementation guidelines for their proposed architecture. **Reviews. ** This Special Issue is complemented by three interesting literature reviews. The first review is focused on how a network can be secured using blockchain technology. [PERSON] et al. [PERSON] et al.