Publikationen

Autor	Banegas, Gustavo; Krämer, Juliane; Lange, Tanja; Meyer, Michael; Panny, Lorenz; Reijnders, Krijn; Sotáková, Jana; Trimoska, Monika
Datum	2023
Art	Conference Proceedings
Abstrakt	We investigate a new class of fault-injection attacks against the CSIDH family of cryptographic group actions. Our disorientation attacks effectively flip the direction of some isogeny steps. We achieve this by faulting a specific subroutine, connected to the Legendre symbol or Elligator computations performed during the evaluation of the group action. These subroutines are present in almost all known CSIDH implementations. Post-processing a set of faulty samples allows us to infer constraints on the secret key. The details are implementation specific, but we show that in many cases, it is possible to recover the full secret key with only a modest number of successful fault injections and modest computational resources. We provide full details for attacking the original CSIDH proof-of-concept software as well as the CTIDH constant-time implementation. Finally, we present a set of lightweight countermeasures against the attack and discuss their security.
Konferenz	42nd Annual International Conference on the Theory and Applications of Cryptographic Techniques
ISBN	978-3-031-30588-7
ISSN	0302-9743
Serie	Lecture Notes in Computer Science
In	Advances in Cryptology - EUROCRYPT 2023, p.310-342
Publisher	Springer
Url	https://tubiblio.ulb.tu-darmstadt.de/id/eprint/138907

Disorientation Faults in CSIDH