On the supersingular GPST attack

The main attack against static-key supersingular isogeny Diffie–Hellman (SIDH) is the Galbraith–Petit–Shani–Ti (GPST) attack, which also prevents the application of SIDH to other constructions such as non-interactive key-exchange. In this paper, we identify and study a specific assumption on which t...

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Bibliographic Details
Main Authors: Basso Andrea, Pazuki Fabien
Format: Article
Language:English
Published: De Gruyter 2021-09-01
Series:Journal of Mathematical Cryptology
Subjects:
Online Access:https://doi.org/10.1515/jmc-2021-0020
Description
Summary:The main attack against static-key supersingular isogeny Diffie–Hellman (SIDH) is the Galbraith–Petit–Shani–Ti (GPST) attack, which also prevents the application of SIDH to other constructions such as non-interactive key-exchange. In this paper, we identify and study a specific assumption on which the GPST attack relies that does not necessarily hold in all circumstances. We show that in some circumstances the attack fails to recover part of the secret key. We also characterize the conditions necessary for the attack to fail and show that it rarely happens in real cases. We give a link with collisions in the Charles-Goren-Lauter (CGL) hash function.
ISSN:1862-2984