Physical Attestation in the Smart Grid for Distributed State Verification

A malicious process in a distributed system can fabricate its internal state in its communications with its peers. These state fabrications can cause other processes in the distributed system to make incorrect control decisions. Smart grid systems have a unique advantage in the detection of falsified state attacks because process control decisions have an observable effect on a shared physical infrastructure. The physical infrastructure acts as a high-integrity message channel that broadcasts changes in individual process states. This work proposes a new distributed security mechanism called physical attestation that combines physical feedback with methods from computer security to detect state fabrications in the smart grid. The theory of physical attestation is proven using an information flow security property called nondeducibility, and supported with experimental results from a simulation test bed.