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

We have two openings at our Department of Information Security and Communication Technology at NTNU: Associate Professor in Cryptographic Engineering: www.jobbnorge.no/en/available... Professor/Associate Professor in Mobile and Computer Networks: www.jobbnorge.no/en/available... Apply by June 12!

The paper shows how to find affine maps agreeing with an S-box on as many as possible inputs. Look for presentation at #Eurocrypt 2026 today! The code is already available. Also check out a vide-coded interactive tool, it's fun to play with: affine.group/pages/greedy...

Might be a bit late on this post, but wanted to take the opportunity to praise my PhD supervisor Colin Boyd, after he became an IACR Fellow this year iacr.org/fellows/2026... ! I think few people can claim to have had a positive impact on as many people's lives as Colin!

By the way as you know lately I have been thinking about cubical structures in terms of derived quadratic forms, and although a bit conceptual it is *amazing* for having a better understanding of what we can do with them. For instance the monodromy leak can be explained in a paragraph:

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...

#KalmarCTF is currently well underway - and we’re once again featuring prizes sponsored by @hex-rays.bsky.social and Zellic ! Come play along by visiting kalmarc.tf

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

Published an opinion piece (in Norwegian) about PQC (yay) vs QKD (buu) in @digi.no today, together with @jonathan.isogeny.club, Kristian Gjøsteen (NTNU), Øyvind Ytrehus (UiB), and Morten Øygarden (UiB): www.digi.no/artikler/deb...

Continuation and end of the thread started here: bsky.app/profile/dami... # Part 4: Speculations Previously: - Part 1: CSIDH bsky.app/profile/dami... - Part 2: SIDH bsky.app/profile/dami... - Part 3: MIKE bsky.app/profile/dami...

I am very happy to announce that thanks to the hard work of many people (The "MIKE Team"), we now have a working implementation in SageMath of MIKE (Module Isogeny Key Exchange).

Thomas Decru, Sabrina Kunzweiler: Abelian surfaces in Hesse form and explicit isogeny formulas https://arxiv.org/abs/2601.05922 https://arxiv.org/pdf/2601.05922 https://arxiv.org/html/2601.05922

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).

New year, new pairing

TL;DR: See title 🥳

Olingo: Threshold Lattice Signatures with DKG and Identifiable Abort (Kamil Doruk Gur, Patrick Hough, Jonathan Katz, Caroline Sandsbråten, Tjerand Silde) ia.cr/2025/1789

For those who missed it, the recording is live! www.youtube.com/watch?v=lvhh...

And you solve the failure rate problem, which was a big source of trouble in the previous implementation. And the new algorithm is simpler to implement! So very exciting result! (Although I had been spoiled already by @jonathan.isogeny.club talk at Bordeaux in May :))

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

... The paper might have been out for less than 24 hours, but that is clearly plenty for yx7 to implement a more computer-algebra friendly implementation that works for any "nice" order! 🥳🥳 github.com/yyyyx4/qlapo...

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

The EU Parliament has published a new proposal for Chat Control to mass-surveil all digital communication in Europe. The proposal is ineffective, weakens secure communication, and violates basic human privacy. This must be stopped immediately. #ChatControl csa-scientist-open-letter.org/Sep2025

Perhaps @jonathan.isogeny.club really really hates embedded devices?

Some impressions of Longyearbyen from the last few days.

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

Evaluation of Modular Polynomials from Supersingular Elliptic Curves (Maria Corte-Real Santos, Jonathan Komada Eriksen, Antonin Leroux, Michael Meyer, Lorenz Panny) ia.cr/2025/1154

Registration for the Leuven Isogeny Days 6 is now open! 📅 10–12 Sept 2025 @ KU Leuven Morning: research talks Afternoon: brainstorming sessions More info: www.esat.kuleuven.be/cosic/projec... #isogeny #isocrypt #erc #postquantum

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...

We are hosting the Information Security Conference (ISC) 2025 at Sungkyunkwan University! ISC is a long-standing security conference with a 28-year history Prof. Hyungjoon Kevin Koo and Hojoon Lee will jointly serve as General Chairs this year. CFP: isc25.skku.edu/call-for-pap...

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

🥇The paper "PRISM: Simple And Compact Identification and Signatures From Large Prime Degree Isogenies", co-authored by COSIC, has won the best paper award at @IACR_News #PKC 2025 in Røros, Norway. #pkc2025 Link: link.springer.com/chapter/10.1...

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!

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.

IACR Public Key Cryptography 2025 registration is open! Please check out pkc.iacr.org/2025/registr... to attend the conference in Røros, Norway from May 12 to 15 🤩 @bordekock.bsky.social , @tiborj.bsky.social

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!

GG everyone who played #KalmarCTF 2025! Writeups for my two challs: MonoDOOM: jonathke.github.io/monoDOOM A chal based on a sick sidechannel attack by @damienrobert.bsky.social ! Not-so-complex multiplication: jonathke.github.io/not-so-complex An easy chal based on complex multiplication.

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

#𝗞𝗮𝗹𝗺𝗮𝗿𝗖𝗧𝗙 𝟮𝟬𝟮𝟱 𝗶𝘀 𝗷𝘂𝘀𝘁 𝗮𝗿𝗼𝘂𝗻𝗱 𝘁𝗵𝗲 𝗰𝗼𝗿𝗻𝗲𝗿 - 𝗰𝗼𝗺𝗲 𝗰𝗼𝗺𝗽𝗲𝘁𝗲 𝘄𝗶𝘁𝗵 𝘁𝗵𝗲 𝗯𝗲𝘀𝘁 𝗰𝗼𝗺𝗽𝗲𝘁𝗶𝘁𝗶𝘃𝗲 𝗵𝗮𝗰𝗸𝗲𝗿𝘀 𝗳𝗿𝗼𝗺 𝗮𝗿𝗼𝘂𝗻𝗱 𝘁𝗵𝗲 𝘄𝗼𝗿𝗹𝗱 𝗮𝗻𝗱 𝘄𝗶𝗻 𝗴𝗿𝗲𝗮𝘁 𝗽𝗿𝗶𝘇𝗲𝘀! (6x IDAPro from @hex-rays.bsky.social) Mark your calendars for March 7th - 9th, 2025, and gear up for a 48-hour showdown of skill, and pure #CTF & #hacking grit.

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! 🥳

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