Design and implementation of rotation symmetric S-boxes with high nonlinearity and high DPA resilience

In this paper we propose a construction and implementation for a class of rotation-symmetric S-boxes (RSSBs) with good cryptographic properties and improved DPA resilience. The S-boxes are constructed from rotation symmetric Boolean functions (RSBFs) and these RSBFs were searched to avoid any fixed points in the RSSB maps. In literature, search of RSSBs included those consisting of fixed points which is considered to be a weakness in the S-box constructions. We present some new properties of RSSBs and find that the search space of RSSBs with fixed points is of exponential order. We also present the hardware architecture of the RSSBs with no fixed points and the corresponding implementations on Xilinx Virtex-5 FPGA device on SASEBO-GII development board and perform a correlation analysis DPA of AES which include these RSSBs. The RSSBs from the proposed class when incorporated in AES, required more power traces compared to the AES containing Rijndael S-box which indicates that the DPA resilience of the proposed RSSBs is higher than that of the AES Rijndael S-box. Also we present the correlation analysis DPA results on the look-up table, distributed memory and block memory based implementations of some of the RSSBs from the proposed class and compare the results with those of the respective implementations of AES-128 Rijndael S-box.