Generalized Spectral Approach to Speed up the Correlation Power Analysis

As shown previously in Sect. 3.2.3, the Correlation Power Analysis (CPA) is a method that allows to recover the secret information concealed in embedded devices [1]. It consists in leveraging the Pearson correlation coefficient as a way to relate an assumed model with the measured power consumed during the running of the operations that involve a secret subkey. Power analysis attacks are based on the principle that the instantaneous power consumption of a cryptographic device depends on the processed data and on the performed operations [2]. During a symmetric protocol, those operations are in particular processed by a non-linear function called S-box which is parametrized by a secret key and the involved message [3, 4].