Smart Grid Security : Challenges and Solutions

State estimation is an important power system tool used to best estimate the system state through analysis of remotely collected sensor measurements and the power system topology. The reliability of the estimated output depends on the quality of the input measurements. Therefore, grid operators use Bad Data Detection (BDD) techniques to filter out grossly erroneous measurements from the state estimator’s calculations. However, an attacker with knowledge of the power system model can corrupt a carefully selected set of measurements to introduce arbitrary errors into certain state variables while bypassing existing BDD techniques. A possible defense to such attacks is to ensure end-to-end secure delivery of the sensor measurements by enforcing message authentication and integrity check at the application layer. Implementing such defense mechanisms requires designing an efficient key management scheme that provides the foundation for the secure generation, storage, and distribution of cryptographic keys. The effectiveness of the defense mechanisms also depends on the level of protection afforded to the cryptographic keys. One solution to protect cryptographic keys is to adopt tamperproof hardware tokens such as the Trusted Platform Module (TPM). However, the security properties of a TPM can also be exploited by an attacker for malicious purposes unless the security credentials that are used to authorize TPM functionalities are safely handled.