Cryptology ePrint Archive: Report 2019/742

Vulnerability Analysis of a Soft Core Processor through Fine-grain Power Profiling

William Diehl and Abubakr Abdulgadir and Jens-Peter Kaps

Abstract: Embedded microprocessors are an important component of reconfigurable architectures. Fine-grain (e.g., cycle-accurate) power analysis of such processors has been used to improve power and energy efficiency, and detect implementation vulnerabilities, in embedded applications. However, such analysis is difficult to conduct; it requires either specialized and often expensive equipment, or construction of test architectures using disparate acquisition and analysis tools. In this research, we expand the Flexible Open-source workBench fOr Side-channel analysis (FOBOS) to facilitate exact time-domain correlation of clock cycle and device state to power measurements, and to perform power analysis on a soft core processor. We first validate the fine-grain power analysis capabilities of FOBOS through cycle-accurate analysis of power consumption of AES encryption running on a soft core processor in the Spartan-6 FPGA. We then analyze the results in the context of Simple Power Analysis side-channel attacks, and confirm power correlation of certain instructions with Hamming Weight or Hamming Distance of secret key bytes. Finally, we show that an assumption of a pure Hamming Distance power model for load-to-register instructions is not sufficient for this embedded processor architecture, and that power models using both Hamming Distance and Hamming Weight should be considered for Differential Power Analysis.

Category / Keywords: implementation / Cryptography, FPGA, microprocessor, side channel, DPA, SPA

Date: received 23 Jun 2019

Contact author: wdiehl at vt edu,aabdulga@gmu edu,jkaps@gmu edu

Available format(s): PDF | BibTeX Citation

Version: 20190625:195231 (All versions of this report)

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