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 !

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.

Registration to the SQIparty is open, free, and we have a first sketch of a program! www.cig.udl.cat/SQIparty2025... Register and plan your travel quickly: the rooms are reserved only until Thursday! See you in Lleida!

Models of Kummer lines and Galois representations (Razvan Barbulescu, Damien Robert, Nicolas Sarkis) ia.cr/2025/543

Is this what it feels like to have a baby? (Defense is May 12th, be there or be square!)

> claims no new results > adds in a tiny new result anyway > ??? anyway, enjoy the read!

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

Just way too many great isogeny papers for a single day!!! - KLPT^2 (eprint.iacr.org/2025/372) - Security of SQIsign (eprint.iacr.org/2025/379) - PEGASIS (eprint.iacr.org/2025/401) Only 147 pages of 'must read' material added to the backlog

At the right level pf abstraction, we present an effective group action: Its so efficient, that frob is sufficient; another win for the isogeny-faction! 🥳

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.

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

Let's welcome the new postdoctoral researcher in our team: Krijn Reijnders! "I chose COSIC because of its excellent research group in cryptography, in particular isogeny-based cryptography, and, of course, the unlimited fries at lunch." 🍟#choosecosic

New paper is out where we build a brand new isogeny-based signature! 🎉 - It's a hash-and-sign signature, which makes it more flexible for advanced constructions - Security depends on a new problem: computing prime-degree isogenies - Performance is comparable to SQIsign2D - Conceptually simpler

Throwback Thursday: what are your favorite reviewer quotes? I'll start: "I wonder how it would come to somebody's mind that such a simplistic thing happens." I'll admit, I did think at first this simplistic thing happened.

Absolutely thrilled for season six of the Isogeny Club (isogeny.club) starting February 25th by a talk by Abel Laval!

PRISM: Simple And Compact Identification and Signatures From Large Prime Degree Isogenies (Andrea Basso, Giacomo Borin, Wouter Castryck, Maria Corte-Real Santos, Riccardo Invernizzi, Antonin Leroux, Luciano Maino, Frederik Vercauteren, Benjamin Wesolowski) ia.cr/2025/135

Really excited to finally share PRISM, a new isogeny-based signature 🥳 joint work with lots of awesome people. eprint.iacr.org/2025/135

Excited for these developments: acornprover.org Make theorem provers read like mathematics in papers, and let AI solve the gap between the readable proof and the formal proof. Then verify the formal proof, or the AI asks for more input from the writer on parts of the proof it doesn't "get"

dCTIDH: Fast & Deterministic CTIDH (Fabio Campos, Andreas Hellenbrand, Michael Meyer, Krijn Reijnders) ia.cr/2025/107

Finally, a state-of-the-art version of CTIDH! That is, deterministic and a prime of 2048 bits. We introduce a new batching strategy we call "wombats", making dCTIDH five times faster than deterministic CSIDH. Surprisingly, it even beats "non-deterministic" CTIDH. See eprint.iacr.org/2025/107

It's ya boy @jonathankeriksen.bsky.social , right here on Bluesky. If this doesn't convince people to adopt Bluesky, nothing will

As a Christmas gift for everyone, we have one exciting final talk of this season! Join the #isogenyclub next Tuesday (17th Dec), where Sina Schaeffler will talk about constant-time lattice reduction for SQIsign. More info at isogeny.club

Sofía Celi joins as new co-editor of eprint.iacr.org. The core of IACR is volunteer effort, and it's always good to welcome someone new. @claucece