Smaller Sphincs$^{+}$

Scott Fluhrer; Quynh Dang

Paper 2024/018 Original: eprint.iacr.org/2024/018 ↗

Smaller Sphincs$^{+}$

Scott Fluhrer

Quynh Dang

Abstract

NIST published FIPS 205 based on the specification of Sphincs$^{+}$. A formula to determine the security strength of a given parameter set is listed in SPHINCSsubmission31. It is quite complex to use that formula to get the security degradation behavior based on different increases in the number of signatures (called $2^{m}$ in this paper) per signing key. The task would become even more complex when we need to compare the security degradation characteristics of many parameter sets. In this paper, we provide a simpler formula to determine the security strengths of a given parameter set at various numbers of signatures produced by one signing key. With this new formula, the task of comparing parameter sets, especially, their security degradation characteristics become easy and that allowed us to search for best parameter sets for users to consider to use and for standard bodies to consider for standardization.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Preprint.
History: 2025-01-16: last updated; 2024-01-05: published
Short URL: https://ia.cr/2024/018
License: https://creativecommons.org/publicdomain/zero/1.0/

BibTeX

@misc{cryptoeprint:2024/018,
      author = {Scott Fluhrer and Quynh Dang},
      title = {Smaller Sphincs$^{+}$},
      howpublished = {Cryptology {ePrint} Archive, Paper 2024/018},
      year = {2024},
      url = {https://eprint.iacr.org/2024/018}
}