  We consider feedback control systems where sensor readings may be compromised
by a malicious attacker intending on causing damage to the system. We study
this problem at the supervisory layer of the control system, using discrete
event systems techniques. We assume that the attacker can edit the outputs from
the sensors of the system before they reach the supervisory controller. In this
context, we formulate the problem of synthesizing a supervisor that is robust
against the class of edit attacks on the sensor readings and present a solution
methodology for this problem. This methodology blends techniques from games on
automata with imperfect information with results from supervisory control
theory of partially-observed discrete event systems. Necessary and sufficient
conditions are provided for the investigated problem.
