Information leakage from robust codes protecting cryptographic primitives

Cryptographic hardware primitives are subject to fault injection attacks. Security-oriented codes are considered the most powerful technique for detecting such attacks. They provide (probabilistic) guarantees for the detection of maliciously injected faults even under the assumption of a sophisticated attacker with access to powerful equipment. In this chapter, we revisit the earlier finding that error-detection infrastructure may increase the undesired information leakage. It is shown that the probability of an attack to be undetected by the best robust codes known today is exponentially smaller than the entropy loss due to information leak from the checker. This means that an attack will be detected far before the attacker can acquire significant information. The analysis is constrictive; given a bound for acceptable information leakage, it allows the designer to easily choose the number of redundant bits required to detect the attack before this bound is reached.