Encrypted Control for Networked Systems AN ILLUSTRATIVE INTRODUCTION AND CURRENT CHALLENGES

Control systems are rapidly evolving to utilize modern computation and communication tools, such as cloud computing and geographically distributed networks, to improve performance, coverage, and scalability. However, control loops that outsource the computation of privacysensitive data to third-party platforms via public networks are already the subject of cyberattacks involving eaves-dropping and data manipulation. Encrypted control addresses this security gap and ensures the confidentiality of the processed data in the entire control loop by encrypting the information both at the level of transmission (across the network) and at the level of computation (on corrupted computing platforms). This article presents a tutorial-style introduction to this young but emerging field in the framework of secure control for networked dynamical systems with encrypted data. Its focus is on the steps for deriving the encrypted formulations of some specific control algorithms from the standard formulations and discussing the challenges arising in this process, ranging from privacy-aware conceptualizations to changes in computation flows and quantization issues. In conclusion, a list of open problems and new directions to explore is provided to consolidate the area of encrypted control.