Verifiable computations for dynamic encrypted control
For control systems relying on cloud-based encrypted computation, this provides a lightweight integrity verification method without expensive cryptographic protocols.
The paper presents a verification algorithm for linear dynamic encrypted control that uses system-theoretic input-output properties to check cloud computation correctness with minimal overhead, detecting errors with high probability and preventing replay attacks.
Encrypted control can preserve the privacy of data and parameters while the necessary computations can be outsourced to a cloud server. To ensure the integrity of the received values from the cloud, i.e., that they have not been changed, however, strong assumptions or verification algorithms are needed. Previous methods require computationally expensive cryptographic protocols or are only applicable to static computations. In this paper, we present a novel type of verification algorithm for linear dynamic encrypted control. We utilize system-theoretic input-output properties of the controller for artificial challenge signals, which are processed in the cloud in parallel with the requested control input, to check the correctness of the results at the plant. This results in almost no additional computational load, wrong computations are revealed with high probability, and no replay attacks are possible.