Unrolling Cryptographic Circuits: A Simple Countermeasure Against Side-Channel Attacks

  • Shivam Bhasin
  • Sylvain Guilley
  • Laurent Sauvage
  • Jean-Luc Danger
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 5985)


Cryptographic cores are used to protect various devices but their physical implementation can be compromised by observing dynamic circuit emanations in order to derive information about the secrets it conceals. Protection against these attacks, also called side channel attacks are major concern of the cryptographic community. Masking and dual-rail precharge logic are promoted as its countermeasures but each has its own vulnerabilities. In this article, we propose a simple countermeasure which comprises unrolling rounds of a cryptographic algorithm such that multiple rounds are executed per clock cycle. This will require a stronger hypothesis on multiple bits due to deeper diffusion of the key. Results show that it resist against correlation power analysis on Hamming distance and Hamming weight model if the datapath is cleared after each operation. We also evaluated mutual information metric on the design and results show that unrolled DES is less vulnerable.


Data encryption standard side-channel attack architectural countermeasure mutual information metric 


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Copyright information

© Springer-Verlag Berlin Heidelberg 2010

Authors and Affiliations

  • Shivam Bhasin
    • 1
  • Sylvain Guilley
    • 1
  • Laurent Sauvage
    • 1
  • Jean-Luc Danger
    • 1
  1. 1.Département COMELECInstitut TELECOM / TELECOM ParisTech, CNRS LTCI (UMR 5141)PARIS Cedex 13France

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