Cryptology ePrint Archive: Report 2022/448

Attacks Against White-Box ECDSA and Discussion of Countermeasures - A Report on the WhibOx Contest 2021

Sven Bauer and Hermann Drexler and Maximilian Gebhardt and Dominik Klein and Friederike Laus and Johannes Mittmann

Abstract: This paper deals with white-box implementations of the Elliptic Curve Digital Signature Algorithm (ECDSA): First, we consider attack paths to break such implementations. In particular, we provide a systematic overview of various fault attacks, to which ECDSA white-box implementations are especially susceptible. Then, we propose different mathematical countermeasures, mainly based on masking/blinding of sensitive variables, in order to prevent or at least make such attacks more difficult. We also briefly mention some typical implementational countermeasures and their challenges in the ECDSA white-box scenario.

Our work has been initiated by the CHES challenge WhibOx Contest 2021, which consisted of designing and breaking white-box ECDSA implementations, so called challenges. We illustrate our results and findings by means of the submitted challenges and provide a comprehensive overview which challenge could be solved in which way. Furthermore, we analyze selected challenges in more details.

Category / Keywords: public-key cryptography / White-box cryptography, Deterministic ECDSA, Computation analysis, Fault analysis, Countermeasures, CHES Challenge, WhibOx Contest 2021

Date: received 8 Apr 2022

Contact author: Friederike Laus at bsi bund de

Available format(s): PDF | BibTeX Citation

Version: 20220412:074418 (All versions of this report)

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