Paper 2026/2451

Extended biprojective APN functions

Nadiia Ichanska, University of Bergen
Nikolay Kaleyski, University of Bergen
Abstract

Almost perfect nonlinear (APN) functions provide optimal resistance to differential cryptanalysis in characteristic two, and constructing new infinite families inequivalent to the known ones remains an important problem in the study of cryptographic functions. We introduce extended biprojective functions, obtained by augmenting biprojective polynomials with truncated trace terms, and establish a new infinite family of quadratic APN functions. To investigate these constructions, we develop an efficient APN test based on the ranks of binary matrices and employ it in exhaustive searches in dimensions up to 28. Using ortho-derivative differential spectra to distinguish CCZ-equivalence classes, we identify APN functions inequivalent to known families and uncover a systematic pattern across dimensions, leading to conjectures on further infinite families of quadratic APN functions.

Metadata
Available format(s)
PDF
Category
Secret-key cryptography
Publication info
Preprint.
Keywords
APN functionsvectorial Boolean funcitonsinfinite families
Contact author(s)
ichanadia235 @ gmail com
History
2026-10-14: revised
2026-10-12: received
See all versions
Short URL
https://ia.cr/2026/2451
License
Creative Commons Attribution-NonCommercial-NoDerivs
CC BY-NC-ND

BibTeX

@misc{cryptoeprint:2026/2451,
      author = {Nadiia Ichanska and Nikolay Kaleyski},
      title = {Extended biprojective {APN} functions},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/2451},
      year = {2026},
      url = {https://eprint.iacr.org/2026/2451}
}
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