Avoiding Risky Designs When Using Blockchain Technologies in Cyber-Physical Systems

Blockchain has been hailed as an emerging technology with the potential to cause significant impact in a variety of fields. One domain is an application in cyber-physical systems (CPSs), e.g., as a building block for the (Industrial) Internet of Things (IIoT) and Industry 4.0. In this regard, various use cases and designs have been proposed that seek to leverage the desirable properties blockchain technologies seem to offer. While many of the principles behind blockchain have actually been studied under the veil of Byzantine fault tolerance for decades, some approaches, such as relying on game-theoretic incentives and proof-of-work (PoW), are not yet fully understood. This knowledge gap can leave both practitioners and researchers in a difficult position regarding a possible application of such technologies, as it is often unclear what guarantees and characteristics a particular blockchain design actually achieves. This work-in-progress paper provides an overview of blockchain security research, outlines system designs that are likely to exhibit vulnerabilities, and provides examples of potentially insecure proposals in the field of CPSs that employ such designs.