TL;DR: The main idea is that given an p.p.a.v. A and an endomorphism 𝛼 of polarized degree d > 1, the points of A that are "eventually fixed by 𝛼" share similarities to an ab. var. over a finite field (both are naturally Zhat-modules), and thus Bruin's formula for the Tate-pairing generalizes 🥳

A computational framework for principally polarized abelian varieties and applications (Maria Corte-Real Santos, Etienne Piasecki, Benjamin Wesolowski) ia.cr/2026/1142

Round 3 of the NIST additional signatures process announced! 🎉 And SQIsign is part of it!! ⛷️⛷️

Even though its not actually post-quantum crypto, I would never pass on a cool application of the Tate pairing: Much faster subgroup membership testing! (the credits go to the rest of the team, though, who write amazingly fast code!!)

Looking forward to AM-PQC 2026, the Workshop on Algebraic Methods in Post-Quantum Cryptography this August in Macedonia! pqcrypto.cs.ru.nl/ampqc/ Stipends for students are available. Apply before May 4th!

Pierre Pébereau just joined COSIC as a postdoc in Fre Vercauteren's team: "I chose COSIC to work with excellent researchers on the analysis of post-quantum signature algorithms." #choosecosic

from @bwesterb.bsky.social: bas.westerbaan.name/notes/2026/0...

I should add to this: winner of best paper award at Eurocrypt 2026!! As a single author. During his PhD. Incredible achievement!(protip: he will graduate soon-ish 👀)

In honor of April Fool's Day (which has already started in Australia), I offer you debrisprint.iacr.org for AI-generated cryptology content.

Writeup of the crypto-challenge MonoDOOM ETERNAL from #KalmarCTF - A follow up from last-years MonoDOOM challenge, this time with botched side-channel protection! jonathke.github.io/monoDOOM-ETE...

We still have a few spots left at MaGIC! Registration closes this week... Hurry up if you want to be on top of all the latest news on Cryptographic Group Actions! magic-workshop.github.io

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 second variant (salt-PRISM) is implemented in C. We find that signing is between 1.4 and 1.6 times faster than SQIsign, whereas verification is between 1.2 times slower to 1.01 times faster. Notably, for Level V, salt-PRISM is faster than SQIsign in both. github.com/mariascrs/PR...

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

PRISM with a pinch of salt: Simple, Efficient and Strongly Unforgeable Signatures from Isogenies (Andrea Basso, Giacomo Borin, Wouter Castryck, Maria Corte-Real Santos, Riccardo Invernizzi, Antonin Leroux, Luciano Maino, Frederik Vercauteren, Benjamin Wesolowski) ia.cr/2026/443

We're organizing a workshop on cryptographic group actions bringing together the isogeny and code communities. The workshop is just before Eurocrypt, a quick train away from Rome in the beautiful Marche. Early registration ends this week, so grab your spot soon! magic-workshop.github.io

Breaking digital signatures from tropical matrix semirings (Alessandro Sferlazza) ia.cr/2026/327

Tripling on Hessian curves via isogeny decomposition (Thomas Decru, Sabrina Kunzweiler) ia.cr/2026/334

📢📢📢 𝐌𝐚𝐆𝐈𝐂 𝟐𝟎𝟐𝟔 𝐌𝐚𝐫𝐜𝐡𝐞 𝐖𝐨𝐫𝐤𝐬𝐡𝐨𝐩 𝐨𝐧 𝐆𝐫𝐨𝐮𝐩 𝐀𝐜𝐭𝐢𝐨𝐧𝐬 𝐢𝐧 𝐂𝐫𝐲𝐩𝐭𝐨𝐠𝐫𝐚𝐩𝐡𝐲 In May 5-8, let's all gather together to speak about Group Actions! Early registration until March 8! Organized with Marco Baldi, @bsky.defeo.lu, @giacomoborin.bsky.social, @andreavbasso.bsky.social magic-workshop.github.io

Silicon Valley’s alliance with Donald Trump was a mask off moment and showed the world we can’t depend on US tech companies. For the past few months, I’ve been trying to get off US tech and I put together a guide so you find alternatives too. I hope you find it helpful!

New year, new pairing

🎄 Happy holidays from all of us in the COSIC research group! Proof that science is better with friends.

Dear publishers, this may come as a shock to you, but in general, I do not want to download a tiny .bib file for every reference. I simply want to copy-paste.

Catch up on last weeks Isogeny Club talk! We welcomed Eli Orvis who taught us about abstract isogeny graphs: www.youtube.com/watch?v=Gzcc...

Great news: the paper "Integral cryptanalysis in characteristic $p$" by our researchers Tim Beyne & Michiel Verbauwhede will receive the Best Theory and Early Career Award at #Asiacrypt 2025! asiacrypt.iacr.org/2025/program...

Last week at The Isogeny Club we had a great talk by Sebastian Spindler about modular curves! Check it out here: www.youtube.com/watch?v=EDU7... Be sure to join us again next Tuesday at the usual time :) isogeny.club

The Isogeny Club Season 7 starts today! At 5pm CEST, Bruno Sterner will talk about finding large smooth twins from short lattice vectors. More details at isogeny.club

The impact of Alfred Menezes in cryptography is profound. Francisco RH and I are organizing an afternoon session in Latincrypt to celebrate Alfred's career: menezesfest.info If you're coming to Medellín, consider attending!

Announcing The Isogeny Problems! A curated list of the seven foremost unsolved problems in isogeny-based cryptography. Solving one of these profound questions would mark a monumental advance, and as a resolver you'd get eternal honor and epic rewards! Full list: isogeni.es/problems

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

"Industry perspectives on implementation and deployment" by Bas Westerbaan (Cloudfare) today at the PQCSA Workshop on Tackling the Quantum Threat in Athens. #PQCSA #PQC #postquantum #eudigital

🔐 You're invited! Join us on 18 Nov 2025 in Leuven (Belgium) for the #IEEE Milestone Award Ceremony, honoring #Rijndael, the Belgian cipher selected as #AES, protecting billions worldwide. Register (free) by 25 Oct: rijndael-ieeemilestone.cs.ru.nl/index #CyberSecurity #Cryptography

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

"Simpler and Faster Pairings from the Montgomery Ladder" by Giacomo Pope, Krijn Reijnders (COSIC), Damien Robert, Alessandro Sferlazza & Benjamin Smith published in IACR Communications in Cryptology and online now: cic.iacr.org/p/2/2/29 #ISOCRYPT #ISOCRYPTproject

9 out of 10 dentists recommend solving log(p) KLPT (from @jonathan.isogeny.club's talk at ARCTICCRYPT 2025!)

Should let people know that this exists and was exactly what I was missing in the last 5 years: github.com/martisak/vsc... Simply directly searches dblp from VS Code and copy-pastes the bib-entry into the bib file

An out-of-schedule update to my quantum landscape chart: sam-jaques.appspot.com/quantum_land..., prompted by @craiggidney.bsky.social 's new paper: arxiv.org/abs/2505.15917. A startling jump (20x) in how easy quantum factoring can be! Also: much improved web design!

Single author, fifteen pages, reduces the bit complexity of millenia-old UOV instances!!

Wedges, oil, and vinegar – An analysis of UOV in characteristic 2 (Lars Ran) ia.cr/2025/1143

Yessss!!!

We (finally) published all the material from this course on SQIsign, including lecture slides and exercise sheets for the Sage laboratory. Available here: github.com/andreavico/S...

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

Starting in half an hour!

tl;dr: dr. ✅ Very happy to share that I successfully defended my thesis "Isogenies & Isometries" yesterday! A thrilling experience, would recommend, 10/10

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!

The mystery guest and myself have made it to Paris! Next stop, Barcelona!

Train arriving in Barcelona (or really Tarragona)! We'll see you in Madrid in one week!

As a surprise for everyone attending, we will even have a mystery guest joining us as well, who you don't want to miss! In fact, we have already started the train journey from Leuven! Curious about the mystery guest? Well, what are you waiting for, sign up and find out next weekend!

The Isogeny Club - Brainstorm Days! - This event is a two-day affiliated event at Eurocrypt 2025, hosted in Madrid, Spain, and will take place on Saturday, May 3, and Sunday, May 4. Registration via the Eurocrypt 2025 registration process. isogeny.club/eurocrypt

Good news is that we're still accepting brainstorm topics!! If you have a brainstorm idea, send us a short description by email !