English

Faulty isogenies: a new kind of leakage

Number Theory 2022-03-01 v2 Cryptography and Security

Abstract

In SIDH and SIKE protocols, public keys are defined over quadratic extensions of prime fields. We present in this work a projective invariant property characterizing affine Montgomery curves defined over prime fields. We then force a secret 3-isogeny chain to repeatedly pass through a curve defined over a prime field in order to exploit the new property and inject zeros in the A-coefficient of an intermediate curve to successfully recover the isogeny chain one step at a time. Our results introduce a new kind of fault attacks applicable to SIDH and SIKE.

Keywords

Cite

@article{arxiv.2202.04896,
  title  = {Faulty isogenies: a new kind of leakage},
  author = {Gora Adj and Jesús-Javier Chi-Domínguez and Víctor Mateu and Francisco Rodríguez-Henríquez},
  journal= {arXiv preprint arXiv:2202.04896},
  year   = {2022}
}

Comments

Update: extended countermeasures