Paper 2020/459

Improved Fault Templates of Boolean Circuits in Cryptosystems can Break Threshold Implementations

Debdeep Mukhopadhyay


Fault Template Analysis (FTA) has been shown as a powerful tool for attacking cryptosystems and exposing vulnerabilities which were previously not reported in existing literature. Fault templates can be utilized for attacking block ciphers in middle rounds which were known prior to be resistant against fault attacks. In this paper we revisit the potent of fault templates and show a more systematic methodology to develop fault templates of Boolean circuits using a well known concept in design verification, namely positive Davio's decomposition. We show that the improved FTAs, called FTA2.0, can be used to fault analyze block ciphers in the middle rounds using as few as two bit-flip faults. Further, it can be used to attack TI-implemented block ciphers by considering a Double Bit Upset (DBU) fault in a target share bit. The attack shows that varying the latency of the fault the adversary can obtain unmasked bits and can recover the secret key.

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Preprint. MINOR revision.
Fault AttacksFault TemplatesThreshold ImplementationsMultiple Bit Upset
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debdeep mukhopadhyay @ gmail com
2020-05-13: last of 2 revisions
2020-04-24: received
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      author = {Debdeep Mukhopadhyay},
      title = {Improved Fault Templates of Boolean Circuits in Cryptosystems can Break Threshold Implementations},
      howpublished = {Cryptology ePrint Archive, Paper 2020/459},
      year = {2020},
      note = {\url{}},
      url = {}
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