Security analysis of logic encryption against the most effective side-channel attack: DPA

Logic encryption has recently gained interest as a countermeasure against IP piracy and reverse engineering attacks. A secret key is used to lock/encrypt an IC such that the IC will not be functional without being activated with the correct key. Existing attacks against logic encryption are of theoretical and/or algorithmic nature. In this paper, we evaluate for the first time the security of logic encryption against side-channel attacks. We present a differential power analysis attack against random and strong logic encryption techniques. The proposed attack is highly effective against random logic encryption, revealing more than 70% of the key bits correctly in 50% of the circuits. However, in the case of strong logic encryption, which exhibits an inherent DPA-resistance, the attack could reveal more than 50% of the key bits in only 25% of the circuits.