Paper 2024/1233

Binding Security of Implicitly-Rejecting KEMs and Application to BIKE and HQC

Juliane Krämer, University of Regensburg
Patrick Struck, University of Konstanz
Maximiliane Weishäupl, University of Regensburg
Abstract

In this work, we continue the analysis of the binding properties of implicitly-rejecting key-encapsulation mechanisms (KEMs) obtained via the Fujisaki-Okamoto (FO) transform. These binding properties, in earlier literature known under the term robustness, thwart attacks that can arise when using KEMs in larger protocols. Recently, Cremers et al. (ePrint'24) introduced a framework for binding notions, encompassing previously existing but also new ones. While implicitly-rejecting KEMs have been analyzed with respect to multiple of these notions, there are still several gaps. We complete the picture by providing positive and negative results for the remaining notions. Further, we show how to apply our results to the code-based KEMs BIKE and HQC, which are among the round-4 candidates in NISTs PQC standardization process. Through this, we close a second gap as our results finish the analysis of the binding notions for the NIST round-4 KEMs.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint.
Keywords
KEMKey-Encapsulation MechanismRobustnessBindingPQCBIKEHQC
Contact author(s)
juliane kraemer @ ur de
patrick struck @ uni-konstanz de
maximiliane weishaeupl @ ur de
History
2024-08-05: approved
2024-08-02: received
See all versions
Short URL
https://ia.cr/2024/1233
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2024/1233,
      author = {Juliane Krämer and Patrick Struck and Maximiliane Weishäupl},
      title = {Binding Security of Implicitly-Rejecting {KEMs} and Application to {BIKE} and {HQC}},
      howpublished = {Cryptology {ePrint} Archive, Paper 2024/1233},
      year = {2024},
      url = {https://eprint.iacr.org/2024/1233}
}
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