Improved Cryptanalysis of HFERP: Unseen Implications of the Simple Attack

Published

April 13, 2024

Author(s)

Max Cartor, Ryann Cartor, Hiroki Furue, Daniel Smith-Tone

Abstract

In this paper we introduce a new attack on the multivariate encryption scheme HFERP, a big field scheme including an extra variable set, additional equations of the UOV or Rainbow shape as well as additional random polynomials. Our attack brings several parameter sets well below their claimed security levels. The attack combines novel methods applicable to multivariate schemes with multiple equation types with insights from the Simple Attack that broke Rainbow in early 2022, though interestingly the technique is applied in an orthogonal way. This work demonstrates that there exist previously unknown impacts of the above work well beyond the scope in which they were derived.

Proceedings Title

Public-Key Cryptography – PKC 2024

Volume

14601

Conference Dates

April 15-17, 2024

Conference Location

Sydney, AU

Conference Title

PKC 2024

Pub Type

Conferences

Download Paper

https://doi.org/10.1007/978-3-031-57718-5_14

Local Download

Keywords

Multivariate Cryptography, HFERP, Cryptanalysis, MinRank, Simple Attack

Citation

Cartor, M. , Cartor, R. , Furue, H. and Smith-Tone, D. (2024), Improved Cryptanalysis of HFERP: Unseen Implications of the Simple Attack, Public-Key Cryptography – PKC 2024, Sydney, AU, [online], https://doi.org/10.1007/978-3-031-57718-5_14, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=956174 (Accessed October 14, 2025)