1Combined Side-Channel and Fault Analysis Attack on Protected Grain Family of Stream Ciphers

Abstract—In this paper, we first demonstrate a new Dif-ferential Power Analysis (DPA) attack technique against the Grain family of stream ciphers (Grain v1 and Grain-128) by resynchronizing the cipher multiple times with the same value of the secret key and randomly generated different initialization vectors (IVs). Subsequently, we develop a combined side channel and fault analysis attack strategy targeting various fault attack countermeasures for the Grain cipher family. We considered clock glitch induced faults occurring in practice for a hardware implementation of the cipher to devise our novel attack technique. Our proposed combined attack strategy works well even if the useful ciphertexts are not available to the adversary. Further, the power trace classifications of a Grain cipher implementation on SASEBO G-II standard side channel evaluation board is shown in order to validate our proposed attack against the cipher. The captured power traces were analyzed using Least Squares Support Vector Machine (LS-SVM) learning algorithm based multiclass classifiers to classify the power traces into the respective Hamming distance (HD) classes. To extract power samples with high information about HD classes, Signal-to-noise ratio (SNR) metric was chosen for feature selection. The experimental results of power trace classifications of test set showed a high success rate of 98 % when the five largest SNR sample instants over a clock cycle were chosen as features. Our proposed attack strategy can also be extended to other stream cipher designs based on Fibonacci configured shift registers