Decomposed S-boxes and DPA attacks: A quantitative case study using PRINCE

Abstract

Lightweight ciphers become indispensable and inevitable in the ubiquitous smart devices. However, the security of ciphers is often subverted by various types of attacks, especially, implementation attacks such as side-channel attacks. These attacks emphasise the necessity of providing efficient countermeasures. In this paper, our contribution is threefold: First, we propose a method to choose the efficient decomposition of S-box in terms of area. Then we slightly alter the widely used formula to improve the accuracy for weighted sum estimation of the shared S-Box and present the practical implementation of two level decomposition using PRINCE S-Box. Finally, we present the first quantitative study on the efficacy of Transparency Order (TO) of decomposed SBoxes in thwarting a side-channel attack. For PRINCE S-Box we observe that TO-based decomposed implementation has better DPA resistivity than the naive implementation. To benchmark the DPA resistivity of TO(decomposed S-Box) implementation we arrive at an efficient threshold implementation of PRINCE, which itself merits to be an interesting contribution.