par Basso, Andrea;Kutas, Péter;Merz, Simon Philipp;Petit, Christophe 
;Weitkämper, Charlotte
Référence Lecture notes in computer science, 12174 LNCS, page (195-213)
Publication Publié, 2020-04-01
;Weitkämper, CharlotteRéférence Lecture notes in computer science, 12174 LNCS, page (195-213)
Publication Publié, 2020-04-01
Article révisé par les pairs
| Résumé : | The k-SIDH protocol is a static-static isogeny-based key agreement protocol. At Mathcrypt 2018, Jao and Urbanik introduced a variant of this protocol which uses non-scalar automorphisms of special elliptic curves to improve its efficiency. In this paper, we provide a new adaptive attack on Jao-Urbanik’s protocol. The attack is a non-trivial adaptation of Galbraith-Petit-Shani-Ti’s attack on SIDH (Asiacrypt 2016) and its extension to k-SIDH by Dobson-Galbraith-LeGrow-Ti-Zobernig (IACR eprint 2019). Our attack provides a speedup compared to a naïve application of Dobson et al.’s attack to Jao-Urbanik’s scheme, exploiting its inherent structure. Estimating the security of k-SIDH and Jao-Urbanik’s variant with respect to these attacks, k-SIDH provides better efficiency. |
