Analysis and Improvement of the Random Delay Countermeasure of CHES 2009

  • Jean-Sébastien Coron
  • Ilya Kizhvatov
Conference paper

DOI: 10.1007/978-3-642-15031-9_7

Part of the Lecture Notes in Computer Science book series (LNCS, volume 6225)
Cite this paper as:
Coron JS., Kizhvatov I. (2010) Analysis and Improvement of the Random Delay Countermeasure of CHES 2009. In: Mangard S., Standaert FX. (eds) Cryptographic Hardware and Embedded Systems, CHES 2010. CHES 2010. Lecture Notes in Computer Science, vol 6225. Springer, Berlin, Heidelberg


Random delays are often inserted in embedded software to protect against side-channel and fault attacks. At CHES 2009 a new method for generation of random delays was described that increases the attacker’s uncertainty about the position of sensitive operations. In this paper we show that the CHES 2009 method is less secure than claimed. We describe an improved method for random delay generation which does not suffer from the same security weakness. We also show that the paper’s criterion to measure the security of random delays can be misleading, so we introduce a new criterion for random delays which is directly connected to the number of acquisitions required to break an implementation. We mount a power analysis attack against an 8-bit implementation of the improved method verifying its higher security in practice.


Side channel attacks DPA countermeasures random delays 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2010

Authors and Affiliations

  • Jean-Sébastien Coron
    • 1
  • Ilya Kizhvatov
    • 1
  1. 1.Université du LuxembourgLuxembourg

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