Publication

Strong 8-bit Sboxes with Efficient Masking in Hardware

Erik Boss, Vincent Grosso, Tim Güneysu, Gregor Leander, Amir Moradi, Tobias Schneider

In: Conference on Cryptographic Hardware and Embedded Systems 2016. Cryptographic Hardware and Embedded Systems (CHES) August 17-19 Santa Barbara United States Pages 171-193 Springer 2016.

Abstract

Block ciphers are arguably the most important cryptographic primitive in practice. While their security against mathematical attacks is rather well understood, physical threats such as side-channel analysis (SCA) still pose a major challenge for their security. An effective countermeasure to thwart SCA is using a cipher representation that applies the threshold implementation (TI) concept. However, there are hardly any results available on how this concept can be adopted for block ciphers with large (i.e., 8-bit) Sboxes. In this work we provide a systematic analysis on and search for 8-bit Sbox constructions that can intrinsically feature the TI concept, while still providing high resistance against cryptanalysis. Our study includes investigations on Sboxes constructed from smaller ones using Feistel, SPN, or MISTY network structures. As a result, we present a set of new Sboxes that not only provide strong cryptographic criteria, but are also optimized for TI. We believe that our results will found an inspiring basis for further research on high-security block ciphers that intrinsically feature protection against physical attacks.

German Research Center for Artificial Intelligence
Deutsches Forschungszentrum für Künstliche Intelligenz