A Note on Feedback-PRF Mode of KDF from NIST SP 800-108

Ritam Bhaumik; Avijit Dutta; Tetsu Iwata; Ashwin Jha; Kazuhiko Minematsu; Mridul Nandi; Yu Sasaki; Meltem Sönmez Turan; Stefano Tessaro

Paper 2025/1586 Original: eprint.iacr.org/2025/1586 ↗

A Note on Feedback-PRF Mode of KDF from NIST SP 800-108

Ritam Bhaumik

Avijit Dutta

Tetsu Iwata

Ashwin Jha

Kazuhiko Minematsu

Mridul Nandi

Yu Sasaki

Meltem Sönmez Turan

Stefano Tessaro

Abstract

We consider FB-PRF, one of the key derivation functions defined in NIST SP 800-108 constructed from a pseudorandom function in a feedback mode. The standard allows some flexibility in the specification, and we show that one specific instance of FB-PRF allows an efficient distinguishing attack.

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: Preprint.
History: 2025-09-03: last updated; 2025-09-03: published
Short URL: https://ia.cr/2025/1586
License: https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2025/1586,
      author = {Ritam Bhaumik and Avijit Dutta and Tetsu Iwata and Ashwin Jha and Kazuhiko Minematsu and Mridul Nandi and Yu Sasaki and Meltem Sönmez Turan and Stefano Tessaro},
      title = {A Note on Feedback-PRF Mode of KDF from NIST SP 800-108},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/1586},
      year = {2025},
      url = {https://eprint.iacr.org/2025/1586}
}