Paper 2004/360 Original: eprint.iacr.org/2004/360 ↗

Equivalent Keys in HFE, C$^*$, and variations

Christopher Wolf
Bart Preneel
Abstract

In this article, we investigate the question of equivalent keys for two $\mathcal{M}$ultivariate $\mathcal{Q}$uadratic public key schemes HFE and C$^{*--}$ and improve over a previously known result, to appear at PKC 2005. Moreover, we show a new non-trivial extension of these results to the classes HFE-, HFEv, HFEv-, and C$^{*--}$, which are cryptographically stronger variants of the original HFE and C$^*$ schemes. In particular, we are able to reduce the size of the private --- and hence the public --- key space by at least one order of magnitude. While the results are of independent interest themselves, we also see applications both in cryptanalysis and in memory efficient implementations.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint.
History
2005-08-09: last updated
2004-12-16: published
Short URL
https://ia.cr/2004/360
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2004/360,
      author = {Christopher Wolf and Bart Preneel},
      title = {Equivalent Keys in HFE, C$^*$, and variations},
      howpublished = {Cryptology {ePrint} Archive, Paper 2004/360},
      year = {2004},
      url = {https://eprint.iacr.org/2004/360}
}
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