Key recovery attacks on the Legendre PRFs within the birthday bound

Dmitry Khovratovich

Paper 2019/862

Key recovery attacks on the Legendre PRFs within the birthday bound

Dmitry Khovratovich

Abstract

We show that Legendre PRF, recently suggested as an MPC-friendly primitive in a prime field $Z_p$, admits key recovery attacks of complexity $O(\sqrt{p})$ rather than previously assumed $O(p)$. We also demonstrate new attacks on high-degree versions of this PRF, improving on the previous results by Russell and Shparlinski.

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: Preprint. MINOR revision.
Keywords: PRF Legendre tradeoff
Contact author(s): khovratovich @ gmail com
History: 2019-07-25: received
Short URL: https://ia.cr/2019/862
License: CC BY

BibTeX

@misc{cryptoeprint:2019/862,
      author = {Dmitry Khovratovich},
      title = {Key recovery attacks on the Legendre PRFs within the birthday bound},
      howpublished = {Cryptology ePrint Archive, Paper 2019/862},
      year = {2019},
      note = {\url{https://eprint.iacr.org/2019/862}},
      url = {https://eprint.iacr.org/2019/862}
}