  Motivated by the need to secure cyber-physical systems against attacks, we
consider the problem of estimating the state of a noisy linear dynamical system
when a subset of sensors is arbitrarily corrupted by an adversary. We propose a
secure state estimation algorithm and derive (optimal) bounds on the achievable
state estimation error. In addition, as a result of independent interest, we
give a coding theoretic interpretation for prior work on secure state
estimation against sensor attacks in a noiseless dynamical system.
