  The tight coupling between communication and control in cyber-physical
systems is necessary to enable the complex regulation required to operate these
systems. Unfortunately, cyberattackers can exploit network vulnerabilities to
compromise communication and force unsafe decision-making and dynamics. If a
cyberattack is not detected and isolated in a timely manner, the control
process must balance adhering to the received measurement signals to maintain
system operation and ensuring that temporary compromise of the signals does not
force unsafe dynamics. For this purpose, we present and employ a safety
critical controller based on control barrier functions to mitigate attacks
against load frequency control in smart power grids. We validate the paper's
findings using simulation on a high-fidelity testbed.
