Amplified Differential Power Cryptanalysis on Rijndael Implementations with Exponentially Fewer Power Traces

摘要

Recently, many research works have been conducted about how to carry out physical cryptanalysis on cryptographic devices by exploiting any possible leaked information through side channels. Research results were also reported on how to develop countermeasures against existing physical cryptanalysis. However, very little attention has been paid to deal with the possible mutual relationship between different kinds of physical cryptanalysis when designing a specific countermeasure. In this paper, it is pointed out that enhanced implementations of the Rijndael cipher (AES) against timing cryptanalysis and simple power cryptanalysis (SPA) may unfortunately become more vulnerable to the differential power cryptanalysis (DPA). Technically speaking, based on Sommer's work and experiments presented in CHES 2000, this new DPA on the above mentioned Rijndael implementations enables a much more significant observable peak within the differential power trace. This makes the DPA attack be more easier with fewer required power traces.