On the Security of a Unified Countermeasure

Implementation attacks are a major threat for cryptographic applications. Recently, Baek and Vasyltsov (ISPEC 2007) proposed a unified countermeasure for protecting elliptic curve implementations against a variety of implementation attacks, including differential power attacks and fault attacks. This paper studies the security of this countermeasure. In particular, it shows that the fault coverage is less than what was anticipated. Further security weaknesses are also pointed out.