Paper 2013/697 Original: eprint.iacr.org/2013/697 ↗

A More Efficient AES Threshold Implementation

Abstract

Threshold Implementations provide provable security against first-order power analysis attacks for hardware and software implementations. Like masking, the approach relies on secret sharing but it differs in the implementation of logic functions. At \textsc{Eurocrypt} 2011 Moradi et al. published the to date most compact Threshold Implementation of AES-128 encryption. Their work shows that the number of required random bits may be an additional evaluation criterion, next to area and speed. We present a new Threshold Implementation of AES-128 encryption that is 18\% smaller, 7.5\% faster and that requires 8\% less random bits than the implementation from \textsc{Eurocrypt} 2011. In addition, we provide results of a practical security evaluation based on real power traces in adversary-friendly conditions. They confirm the first-order attack resistance of our implementation and show good resistance against higher-order attacks.