Polar differential power attacks and evaluation

Side channel attacks (SCAs) on security software and hardware have become major concerns on computer and system security. The existing SCAs generally require the knowledge of the corresponding cryptographic algorithm and implementation adopted in the target; therefore, they are not fully suitable for practical applications. In this paper, we propose a novel SCA—polar differential power attack (polar DPA). We found that DPA peaks have different biases for different cryptographic algorithms and implementations. Based on these biases, we can successfully attack a block cipher, assuming that the cipher algorithm uses a secret key in its first round, without the knowledge of the cipher algorithm or implementation. Other rounds can be treated as a black box. We present a detailed theoretical analysis and experiment to demonstrate the correctness and efficiency of our scheme. Furthermore, our scheme has demonstrated an improvement over the leakage evaluation scheme due to Ichikawa et al. (CHES 2005). Our evaluation method can be used in electronic design automatic (EDA) flows and can help security circuit designers to understand the data leakage due to SCAs.