Extracting side-channel leakage from round unrolled implementations of lightweight ciphers

EasyChair Preprint 800

Abstract

Energy efficiency and security is a critical requirement for computing at edge nodes. Unrolled architectures for lightweight cryptographic algorithms have been shown to be energy-efficient, providing higher performance while meeting resource constraints. Hardware implementations of unrolled datapaths have also been shown to be resistant to side channel analysis (SCA) attacks due to a reduction in signal-to-noise ratio (SNR) and an increased complexity in the leakage model. This paper demonstrates optimal leakage models and an improved CFA attack which makes it feasible to extract first-order side-channel leakages from combinational logic in the initial rounds of unrolled datapaths. Several leakage models, targeting initial rounds, are explored and 1-bit hamming weight (HW) based leakage model is shown to be an optimal choice. Additionally, multi-band narrow bandpass filtering techniques in conjunction with correlation frequency analysis (CFA) is demonstrated to improve SNR by up to 4×, attributed to the removal of the misalignment effect in combinational logics and signal isolation.  The improved CFA attack is performed on side channel signatures acquired for 7-round unrolled SIMON datapaths, implemented on Sakura-G (XILINX spartan 6, 45nm) based FPGA platform and a 24× reduction in minimum-traces-to-disclose (MTD) for revealing 80% of the key bits is demonstrated with respect to conventional time domain correlation power analysis (CPA). Finally, the proposed method is successfully applied to a fully-unrolled datapath for PRINCE and a parallel round-based datapath for Advanced Encryption Standard (AES) algorithm to demonstrate its general applicability.

Keyphrases: CPA attack, IoT Security, Lightweight Cryptography, Unrolled Architectures, cfa attack, combinational logic, leakage model, narrow bandpass filtering, side-channel analysis, success rate

@booklet{EasyChair:800,
  author    = {Nikhil Chawla and Arvind Singh and Nael Mizanur Rahman and Monodeep Kar and Saibal Mukhopadhyay},
  title     = {Extracting side-channel leakage from round unrolled implementations of lightweight ciphers},
  doi       = {10.29007/k6cr},
  howpublished = {EasyChair Preprint 800},
  year      = {EasyChair, 2019}}