CyPhyCrypt: Advanced Crypto for New and Next-Generation Cyber-Physical Systems

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We are surrounded by an ever-growing number of cyber-physical systems (CPS), such as electronic toll collection, traffic management systems, smart homes or the smart grid. This evolution offers many benefits for users and the society at large, but also comes with serious risks with respect to system security and user privacy. As demonstrated by the numerous attacks that have become public, e.g., targeting smart metering or electronic transportation payments, securing CPS is a non-trivial task. Also, the privacy of users is often neglected, which can impose a major roadblock for the broad acceptance of such systems in Europe.Interestingly, the world of theoretical cryptography offers a large toolbox of advanced protocols (besides mere encryption and signature algorithms) with features that are extremely attractive for protecting next-generation CPS. Unfortunately, these protocols have several shortcomings when applied ina CPS context, such as poor efficiency or missing functionality, preventing an off-the-shelf use. Nevertheless, it seems highly attractive to build CPS security solutions from advanced crypto due to the strong and provable security and privacy guarantees. We believe that this is possible, at least to a certain extent, by carefully re-designing, extending, and composing these building blocks. Indeed, our first results in this field, where we build efficient transit payment systems based on anonymous credentials and electronic cash, support this hypothesis.Hence, the main goal of this project is to develop a toolbox of advanced crypto components suitable for securing CPS. To this end, we will exemplarily study the technical and non-technical requirements of two important classes of CPS, namely Participatory Sensing (PPS) and Vehicle-2-Grid (V2G), where our main focus will be the PPS scenario. Based on this, the suitability of promising instances of advanced crypto protocols such as anonymous credentials, e-cash, reputation, and fair-exchange protocols will be assessed. This will lead to the (re-)design of particular components with the goal to match special requirements. One important goal will be the development of more lightweight instances of these advanced protocols so that they become practical, as well as components with enhanced functionality (e.g., privacy-preserving datamining capabilities). As another important contribution, a complete proof-of-concept security scheme for PPS will be composed based on our toolbox, thereby showing its suitability. Besides the construction, this includes a proof of security for the composition, its secure and efficient implementation on the mobile target platforms and the backend, and the setup of a small-scale prototype. To cope with these challenges requires an interdisciplinary effort of pure and applied cryptography. In contrast, most previous work dealt with isolated CPS security aspects, uses heuristic security techniques or basic crypto, and lacks formal security proofs.