Noname manuscript No. (will be inserted by the editor) Masking vs. Multiparty Computation: How Large is the Gap for AES?

the date of receipt and acceptance should be inserted later Abstract In this paper, we evaluate the performances of state-of-the-art higher-order masking schemes for the AES. Doing so, we pay a particular attention to the comparison between specialized solutions introduced ex-clusively as countermeasures against side-channel anal-ysis, and a recent proposal by Roche and Prouff ex-ploiting MultiParty Computation (MPC) techniques. We show that the additional security features this lat-ter scheme provides (e.g. its glitch-freeness) comes at the cost of large performance overheads. We then study how exploiting standard optimization techniques from the MPC literature can be used to reduce this gap. In particular, we show that “packed secret sharing ” based on a modified multiplication algorithm can speed up MPC-based masking when the order of the masking scheme increases. Eventually, we discuss the random-ness requirements of masked implementations. For this purpose, we first show with information theoretic ar-guments that the security guarantees of masking are only preserved if this randomness is uniform, and ana-lyze the consequences of a deviation from this require-ment. We then conclude the paper by including the cost of randomness generation in our performance eval-uations. These results should help actual designers to choose a masking scheme based on security and perfor-mance constraints