Thomas and I looked at directed isogeny graphs! In dim 1, we often ignore directedness, as there are only 2 "problematic" curves. Not so in dim 2: we analyze the action of automorphisms on level structures and the resulting directed graphs. Crucial: Directed (2,2)-graphs looks Ramanujan after all!

The principal ideal problem for endomorphism rings of superspecial abelian varieties (Wouter Castryck, Jonathan Komada Eriksen, Riccardo Invernizzi, Frederik Vercauteren) ia.cr/2026/454

New PRISM improvements 🥳 We extended our PRISM paper to present two new variants: one that achieves strong unforgeability, and another that allows for smaller parameters and therefore faster signatures! eprint.iacr.org/2026/443.pdf

I am co-organising (with @drl3c7er.bsky.social and Lucjan Hanzlik) a workshop on Privacy-Enhancing Cryptography in Rome on May 10 as an affiliated event to IACR Eurocrypt. Submit your best PEC-work (3-page extended abstract) for presentation by February 25th: privcryptworkshop.github.io

Bit of a last-minute announcement: school on isogenies 9 - 13 Feb at Okinawa Institute of Science and Technology (OIST) groups.oist.jp/tsvp/event/s... Registration deadline is tomorrow (15 Jan).

The Cokernel Pairing (Krijn Reijnders) ia.cr/2026/001

scottaaronson.blog?p=9344 I think this is an incredibly insightful blogpost, I highly recommend reading it, especially the last paragraph.

While I can understand how some reviewers in cryptography research are frustrated with the process, I cannot imagine how bad it is in machine learning. ncfrey.substack.com/p/publishing...

The call for papers for PKC 2026 is out: pkc.iacr.org/2026/callfor...

Bribers, Bribers on The Chain, Is Resisting All in Vain? Trustless Consensus Manipulation Through Bribing Contracts (Bence Soóki-Tóth, István András Seres, Kamilla Kara, Ábel Nagy, Balázs Pejó, Gergely Biczók) ia.cr/2025/1719

TL;DR: we solve norm equations in a better way and get around a 2x improvement to IdealToIsogeny routines crucial in both SQIsign and PRISM.

Qlapoti: Simple and Efficient Translation of Quaternion Ideals to Isogenies (Giacomo Borin, Maria Corte-Real Santos, Jonathan Komada Eriksen, Riccardo Invernizzi, Marzio Mula, Sina Schaeffler, Frederik Vercauteren) ia.cr/2025/1604

Can someone provide me with an explanation how TCHES ended up on some Norwegian list for predatory journals?

Proud moment at #CRYPTO 2025! “KLPT²: Algebraic Pathfinding in Dimension Two and Applications” received the Best Paper Award. 🏆 Co-authored by COSIC’s Wouter Castryck & Thomas Decru (presenter). Read it here: eprint.iacr.org/2025/372

Very sad news

This exactly. And it's not just theoretical, it can happen for real. "The Chinese state-sponsored cyberattack threat managed to infiltrate the "lawful intercept" network connections that police use in criminal investigations." www.darkreading.com/cyber-risk/s...

Yessss!!!

Reminder that the MSCA postdoctoral program exists. If you have a PhD and want to work in a European lab, you have until September to apply. Just contact them now. ec.europa.eu/info/funding...

Orient Express: Using Frobenius to Express Oriented Isogenies (Wouter Castryck, Riccardo Invernizzi, Gioella Lorenzon, Jonas Meers, Frederik Vercauteren) ia.cr/2025/1047

Next week @lucianomaino.bsky.social and I will teach a week-long course on SQIsign at the University of Trento. The course will be both in-person and online: if you're interested, you can tune in Monday morning at 10:30 at unitn.zoom.us/j/88902079708 (details and full schedule in the image below)

CECC 2025 will accept posters, submission deadline is the 23rd May (more details can be found at cecc2025.inf.elte.hu). Also we have great invited speakers (Carla Rafols, Thomas Decru, Stefan Dziembowski), so hope to see you in Budapest!

This is cool heimberger.xyz/oprfs.html

The SQIparty starts on Monday, but it's still time to register! We prepared an exciting program for you with a balanced mix of talks, coding sprints, skillshares and other activities! www.cig.udl.cat/SQIparty2025... See you in Lleida!

New work: we explain cubical arithmetic in simple terms to show you how easy it is to compute pairings. Essentially, you only need to know the Montgomery ladder! As a bonus, pairings from cubical arithmetic are faster than those from Miller's loop for applications in isogeny-based cryptography.

Really excited to share the Decrypting Diversity Summit happening in Montpellier, France from 17-20 June! The goal of the summit is to promote diversity, inclusivity, and gender equality within the cryptography community. For more info: decryptingdiversity.com

Deadline to submit to this conference is today!

The second Levchin Prize goes to the CADO-NFS team: Emmanuel Thomé, Pierrick Gaudry, and Paul Zimmerman! Congratulations! #realworldcrypto

Registration is now open! www.cig.udl.cat/SQIparty2025...

Fancy some isogeny crypto? Join us for a 3-day workshop on isogeny-based cryptography in Lleida, Catalonia, April 28-30 www.cig.udl.cat/icrypto2025_... Brought to you by ULleida's Cryptography+Graphs group, the SQIsign team and friends! Registration and program coming soon Registration is free!

Next week (Tuesday 5pm CET) at The Isogeny Club we'll have Laurane Marco (EPFL) who will talk to us about computing modular polynomials modulo a generic prime! More details at isogeny.club

On the Soundness of Algebraic Attacks against Code-based Assumptions (Miguel Cueto Noval, Simon-Philipp Merz, Patrick Stählin, Akin Ünal) ia.cr/2025/415

16th International Conference on Cryptology AFRICACRYPT 2025 July 21-23, 2025 – Rabat, Morocco 🇲🇦 Extended submission deadline in 1 week: africacrypt2025.sciencesconf.org Submit your best results ! See you in Rabat 🇲🇦 in July 2025.

PEGASIS: Practical Effective Class Group Action using 4-Dimensional Isogenies (Pierrick Dartois, Jonathan Komada Eriksen, Tako Boris Fouotsa, Arthur Herlédan Le Merdy, Riccardo Invernizzi, Damien Robert, Ryan Rueger, Frederik Vercauteren, Benjamin Wesolowski) ia.cr/2025/401

As part of the round-2 NIST submission, we developed a complete proof of security of SQIsign!

Happy to share this work with Paul Frixons, Valerie Gilchrist, Simon-Philipp Merz and Christophe Petit. We show that you have to be careful with new assumptions for cryptographic group actions. Namely for the CSI-SHARK assumption one can significantly beat Kuperberg using Childs-Van Dam

Excited to share this work on 2-dimensional KLPT which is joint work with Wouter Castryck, Thomas Decru, Abel Laval, Christophe Petit and Yan Bo Ti. This could pave the way for a 2-dimensional SQIsign and potentially other applications.