An Efficient Masking Scheme for AES Software Implementations

The development of masking schemes to secure AES implementations against power-analysis attacks is a topic of ongoing research. The most challenging part in masking an AES implementation is the SubBytes operation because it is a non-linear operation. The current solutions are expensive to implement especially on small 8-bit processors; they either need many large tables or require a large amount of operations. In this article, we present a masking scheme that requires considerably less tables and considerably less operations than the previously presented schemes. We give a theoretical proof of security for our scheme and confirm it with actually performed DPA attacks.