ALAFA: Automatic Leakage Assessment for Fault Attack Countermeasures

Assessment of the security provided by a fault attack countermeasure is challenging, given that a protected cipher may leak the key if the countermeasure is not designed correctly. This paper proposes, for the first time, a statistical framework to detect information leakage in fault attack countermeasures. Based on the concept of non-interference, we formalize the leakage for fault attacks and provide a t-test based methodology for leakage assessment. One major strength of the proposed framework is that leakage can be detected without the complete knowledge of the countermeasure algorithm, solely by observing the faulty ciphertext distributions. Experimental evaluation over a representative set of countermeasures establishes the efficacy of the proposed methodology.