Transparency order versus confusion coefficient: a case study of NIST lightweight cryptography S-Boxes

Cybersecurity

Guang Yang¹  Huizhong Li²  Chengbin Jin²  Jingdian Ming²  Yongbin Zhou³ 

[1] Department of Software Engineering and Software Evaluation, Beijing Institute of Computer Technology and Application, 100039, Beijing, China;Institute of Information Engineering, Chinese Academy of Sciences, 100093, Beijing, China;School of Cyber Security, University of Chinese Academy of Sciences, 100049, Beijing, China;Institute of Information Engineering, Chinese Academy of Sciences, 100093, Beijing, China;School of Cyber Security, University of Chinese Academy of Sciences, 100049, Beijing, China;School of Cyber Security, Nanjing University of Science and Technology, 210094, Nanjing, China;

关键词: Side-channel attacks;    NIST lightweight cryptography S-Boxes;    Transparency order;    Confusion coefficient;   

DOI  :  10.1186/s42400-021-00099-1

来源: Springer

【 摘 要 】

Side-channel resistance is nowadays widely accepted as a crucial factor in deciding the security assurance level of cryptographic implementations. In most cases, non-linear components (e.g. S-Boxes) of cryptographic algorithms will be chosen as primary targets of side-channel attacks (SCAs). In order to measure side-channel resistance of S-Boxes, three theoretical metrics are proposed and they are reVisited transparency order (VTO), confusion coefficients variance (CCV), and minimum confusion coefficient (MCC), respectively. However, the practical effectiveness of these metrics remains still unclear. Taking the 4-bit and 8-bit S-Boxes used in NIST Lightweight Cryptography candidates as concrete examples, this paper takes a comprehensive study of the applicability of these metrics. First of all, we empirically investigate the relations among three metrics for targeted S-boxes, and find that CCV is almost linearly correlated with VTO, while MCC is inconsistent with the other two. Furthermore, in order to verify which metric is more effective in which scenarios, we perform simulated and practical experiments on nine 4-bit S-Boxes under the non-profiled attacks and profiled attacks, respectively. The experiments show that for quantifying side-channel resistance of S-Boxes under non-profiled attacks, VTO and CCV are more reliable while MCC fails. We also obtain an interesting observation that none of these three metrics is suitable for measuring the resistance of S-Boxes against profiled SCAs. Finally, we try to verify whether these metrics can be applied to compare the resistance of S-Boxes with different sizes. Unfortunately, all of them are invalid in this scenario.

【 授权许可】

CC BY