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Faster SeaSign Signatures Through Improved Rejection Sampling

  • Thomas DecruEmail author
  • Lorenz Panny
  • Frederik Vercauteren
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 11505)

Abstract

We speed up the isogeny-based “SeaSign” signature scheme recently proposed by De Feo and Galbraith. The core idea in SeaSign is to apply the “Fiat–Shamir with aborts” transform to the parallel repeated execution of an identification scheme based on CSIDH. We optimize this general transform by allowing the prover to not answer a limited number of said parallel executions, thereby lowering the overall probability of rejection. The performance improvement ranges between factors of approximately 4.4 and 65.7 for various instantiations of the scheme, at the expense of roughly doubling the signature sizes.

Keywords

Isogeny-based cryptography Signatures SeaSign Rejection sampling Group actions 

Notes

Acknowledgements

We are thankful to Steven Galbraith for his observation about shorter signatures in Remark 2, and to Taechan Kim for pointing out an error in an earlier version of the script in Appendix A.

Supplementary material

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Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Thomas Decru
    • 1
    Email author
  • Lorenz Panny
    • 2
  • Frederik Vercauteren
    • 1
  1. 1.imec-COSIC, ESAT, KU LeuvenLeuvenBelgium
  2. 2.Department of Mathematics and Computer ScienceTechnische Universiteit EindhovenEindhovenThe Netherlands

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