Sign in

Sabine Oechsner

@proofnerd.bsky.social
266 followers 218 following 79 posts

cryptography and pretty proofs | PL-curious | everything is MPC | assistant professor @ VU Amsterdam soechsner.de

PostsRepliesMedia
Reposted by Sabine Oechsner
Clément Canonne @ccanonne.github.io · 29/09/2026
A very important message from Omer Reingold to our TCS community, especially us (arg, already) senior researchers: "snap out of it." Please, digest, and share. theorydish.blog/2026/09/29/s...
As for depression: the next time you have the urge to lament, or even celebrate, being “the last generation of human mathematicians,” perhaps keep it to yourself. Contemplating the end of your profession from the relative comfort of an established, tenured career is a privilege, and it comes with responsibilities. Senior academics are not merely individual researchers; we are stewards of our field, and we owe our junior colleagues active leadership rather than abandonment.
47120
Reposted by Sabine Oechsner
mccurley.bsky.social @mccurley.bsky.social · 28/09/2026
I'd like to remind IACR members to sign up for discuss.iacr.org so they can participate in the discussion about how to adapt the society to the new world of publishing and conferences. If you don't have an account you can visit iacr.org/discuss/
iacr.org
accounts on discuss.iacr.org
044
Reposted by Sabine Oechsner
Lance Fortnow @lance.fortnow.com · 17/09/2026
STOC call for papers is out. Deadline is November 2. acm-stoc.org/stoc202... New rules for the AI era: limited submissions, public posting and a required video. Is it a coincidence that the camera-ready deadline is April Fools Day?
0125
Reposted by Sabine Oechsner
Chris Peikert @chrispeikert.bsky.social · 10/09/2026
“Now Lean, particularly in Navier-Stokes papers, is being used as a time-stamp, a way to claim your theorem before having to write it up properly in an explainable way.” A sentence that would’ve been seen as the ravings of a madman just ~1 year ago. blog.computationalcomplexity.org/2026/09/navi...
blog.computationalcomplexity.org
Navier-Stokes and Lean
I was working on this week's post on Lean after reading Kevin Hartnett's book  The Proof in the Code: How a Truth Machine Is Transforming Ma...
0248
Reposted by Sabine Oechsner
Schloss Dagstuhl – Leibniz-Zentrum für Informatik (LZI) @dagstuhl.de · 10/09/2026
It is time for possible Dagstuhl proposals again! Proposals can be submitted between October 15 and November 1, 2026. For links to guidelines, more details on the process, and important dates see www.dagstuhl.de/en/institute...
dagstuhl.de
Call for Proposals (Deadline November 1, 2026)
Call for Proposals (Deadline November 1, 2026)
0108
Reposted by Sabine Oechsner
Fredrik Dahlgren @fegge.bsky.social · 09/09/2026
My colleague Marc found a 20-line Lean ”proof” of Fermat’s last theorem that really fits in the margin! 😁 blog.trailofbits.com/2026/09/09/a...
blog.trailofbits.com
A “proof” of Fermat’s Last Theorem that fits the margin
Fermat’s margin was too narrow for his proof. Ours would have fit just fine, thanks to a wonderfully cursed Lean bug.
221
Reposted by Sabine Oechsner
Seny Kamara @senykamara.com · 08/09/2026
Fantastic thread on math’s over-indexing on problem solving but applies to theoretical CS and crypto as well (in fact I think TCS and crypto are worse than math in this regard). Took me a few years after my PhD to converge to this viewpoint as well but I always thought I was just odd
071
Reposted by Sabine Oechsner
🇵🇸Tim Henke (tɪm 'ɦɛŋ.kə) @timhenke.bsky.social · 30/08/2026
I kinda consider this a soft confession to what I was theorising 1) He admits they only care about maths in so far as it brings good PR 2) they're only interested in announcing results that make it sound like they're gonna replace mathematicians ∴) they're optimising for impressive-soundingness
twitter user Noam Brown tweets

Today I was asked why we haven’t announced more math results from Astra since these problems.

At 
@OpenAI
 we aim to devote time to finding and announcing math results from internal models only when they would meaningfully change people’s understanding of the pace of AI progress. Our main focus is shipping great models so everyone can use them to make discoveries of their own.

The post is a quote retweet of a post from August 1st sharing 10 major open problems in mathematics, saying

An internal version of Astra, @OpenAI’s next major model family, solved 10 major open problems in mathematics, quantum complexity, and theoretical computer science.

We believe it will be a major step for scientific reasoning....
1215732
Reposted by Sabine Oechsner
Ben Brubaker @benbenbrubaker.bsky.social · 28/08/2026
My latest for @quantamagazine.org is something a bit different from my usual fare: a first-person essay exploring what theoretical computer science has to do with computers.
quantamagazine.org
Does Computer Science Need Computers? | Quanta Magazine
The theoretical side of the field doesn’t require computing machines. But many questions would never have been posed without them.
0326
Reposted by Sabine Oechsner
FOCS 2026 @focs2026.bsky.social · 24/08/2026
Travel Awards for Students and Postdoctoral Fellows for #FOCS2026: details and application process are available at focs.computer.org/2026/travel-... Apply by ⏰ September 19!
focs.computer.org
Travel Support – FOCS 2026
016
Reposted by Sabine Oechsner
Matthew Green @matthewdgreen.bsky.social · 15/08/2026
I wrote up a new post about what AI software finding might mean for the backdoor debate. blog.cryptographyengineering.com/2026/08/14/e...
blog.cryptographyengineering.com
Everything is about to “go dark”
I’m coming down from spending a few days at Usenix Security, right here in my hometown of Baltimore. This means that my days have been taken up with two kinds of conversation: first, explaini…
810245
Reposted by Sabine Oechsner
Matthew Green @matthewdgreen.bsky.social · 11/08/2026
If you haven’t seen it, this new paper is great. They expand on a blog post I wrote that showed you could replay encrypted reasoning blobs from AI models. And they turned it into a full jailbreak. stolen-thoughts.com
stolen-thoughts.com
Stolen Thoughts
Encrypted chain-of-thought blocks returned by Anthropic, OpenAI and Google APIs are interchangeable across sessions, users and models. We exploit this to decode hidden reasoning at scale.
210534
Reposted by Sabine Oechsner
Tressie McMillan Cottom @tressiemcphd.bsky.social · 01/08/2026
Anyway, your problem isn‘t finding the time to take notes. The problem is that taking notes is thinking and thinking has to be done by someone. women have been doing a lot of metacognition that looks like a task when it’s really thinking.
161867290
Reposted by Sabine Oechsner
mccurley.bsky.social @mccurley.bsky.social · 09/07/2026
The IACR board has put forward a proposal to revamp the publishing of the general conference proceedings for Eurocrypt, Crypto, and Asiacrypt. iacr.org/hybridpropos... I would encourage members to engage in discussion about this on iacr.org/discuss
iacr.org
Concrete Hybrid Journal Proposal
01911
Reposted by Sabine Oechsner
Marcel Keller @mkskeller.bsky.social · 06/07/2026
The documentation now includes a section on security fixes. mp-spdz.readthedocs.io/en/latest/se...
mp-spdz.readthedocs.io
Security Fixes — MP-SPDZ documentation
021
Reposted by Sabine Oechsner
Nils Fleischhacker @cryptomaeher.bsky.social · 02/07/2026
I'm looking for a job! I'm an experienced researcher in cryptography. My focus is on the transition to post-quantum cryptographic protocols and protocols related to blockains. If that sounds like someone you might want to hire or you know someone who might, let's talk!
11412
Reposted by Sabine Oechsner
ePrint Updates @eprint.ing.bot · 30/06/2026
Principles for pRHL Proofs of Cryptographic Protocols: How to Convince EasyCrypt that your Protocol is Secure (Manuel Barbosa, François Dupressoir, Cameron Low, Charlotte Mylog, Sabine Oechsner, Théo Vignon) ia.cr/2026/1334
Abstract. The EasyCrypt proof assistant has been used to successfully formalize security proofs for a wide variety of crypto- graphic primitives. However, attempts at formalizing objects with interactivity, such as protocols, have fared much worse. In this paper, we investigate (some of) the reasons for this difficulty by formalizing a simple interactive key agreement protocol. From a first complete but exploratory proof, to a failed attempt at a structured proof, and to what we believe is an “essential” proof, we identify which proof features contribute most to the complexity of formalization in pRHL. In particular, we argue that difficulties in formalizing the security of interactive protocols in the computational model arise from the fact that such proofs rely on both state and temporal invariants—the former to support cryptographic reasoning, and the latter to support reasoning about the protocol’s structure. We believe that this observation can help build new reasoning tools that can bridge the gap that currently exists between primitive-focused tools and protocol- focused tools.
022
Reposted by Sabine Oechsner
Tianxin Tang @koptxin.bsky.social · 17/06/2026
I am looking for a (fully funded) PhD student working with me in Glasgow on provable security! www.iacr.org/jobs/item/4226
iacr.org
PhD Student
087
Reposted by Sabine Oechsner
Tianxin Tang @koptxin.bsky.social · 12/06/2026
Seems like a nice program. See you at Bristol :) uk-crypto-day.github.io/2026/06/17/u...
uk-crypto-day.github.io
UK Crypto Day
Schedule 09:00 - 09:45 Arrival 09:45 - 10:00: Opening remarks 10:00 - 10:45: Sofia Celi: Threshold Post-Quantum Signatures 10:45 - 11:15: Break 11:15 - 12:00: Thalia Laing: Lessons from deploying LMS ...
011
Reposted by Sabine Oechsner
Miro Haller @mirohaller.bsky.social · 11/06/2026
The Workshop on Attacks in Cryptography 8 (WAC8) website is finally up, and our call for talks is open. Submit your cool cryptanalysis before July 3! We'll also invite speakers. If you had a favorite cryptographic attack from the last two years that we should invite, please put it in the comments.

call for talks

WAC accepts proposals for contributed talks. Submissions will be evaluated based on their relevance to the following topics:
- Cryptanalysis of deployed cryptography
- Cryptanalysis of recently suggested cryptographic schemes or primitives
- New cryptoanalytic techniques
- Systems attacks breaking cryptography or bypassing underlying assumptions

Please include the following information in your contributed talk submission.
- Title.
- Description of the talk content, including: short abstract (to be published on the website on talk acceptance), and one of the following three: extended abstract describing the talk. [preferred option], a full paper and a short description of which aspects the talk will focus on. slides for a presentation, together with either speaker notes or a short outline of the non-visual content of the talk.
- Speaker information: Name, Affiliation, Short bio (to be published on the website on talk acceptance), A brief description of the relevant experience of the speaker, e.g. links to previous talks.

Submit your proposal by email to the organizers at wac@cryptanalysis.fun by July 3, 2026 AoE.
074
Reposted by Sabine Oechsner
COSIC @cosic.bsky.social · 10/06/2026
Check out the latest blog post on our website by Neus Vayà, who attended #TPMPC 2026 in Denmark. In the post, she discusses the paper “When Trying to Catch Cheaters Breaks the MPC” by Andreas Brüggemann and Thomas Schneider: www.esat.kuleuven.be/cosic/blog/t...
esat.kuleuven.be
TPMPC 2026: “When trying to catch cheaters breaks the MPC” - COSIC
COSIC - TPMPC 2026: “When trying to catch cheaters breaks the MPC” (COSIC Cryptography Blog )
001
Reposted by Sabine Oechsner
Shriram Krishnamurthi @shriram.bsky.social · 09/06/2026
As GenAI systems do more and more, even generate proofs, the focus shifts to getting high-quality specifications. What can a *responsible* programmer do? Any solution should generate work that is *meaningful* and *moderate*. We've been working on that! blog.brownplt.org/2026/06/09/p...
blog.brownplt.org
Human Judgment as a Specification
2175
Reposted by Sabine Oechsner
Marcel Keller @mkskeller.bsky.social · 05/06/2026
UNSW Sydney is hiring an associate professor and a lecturer in cryptography, and the description explicitly mentions *secure computation*. Didn't you want to live in the sunniest of the most livable cities in the world?
external-careers.jobs.unsw.edu.au
Associate Professor in Cryptography
Join an organisation that is shaping the future direction of cryptography and secure computation in Australia, in a senior academic role that combines research leadership, strategic contribution, and ...
166
Reposted by Sabine Oechsner
Himanshu @h-vash.bsky.social · 03/06/2026
Just read through this blogpost "Contextualising Cryptography" by @senykamara.com. It hits some of the issues I have been facing in choosing the right problems for my research, even before starting my phd (advisor reveal post coming up soon). senykamara.substack.com/p/contextual...
senykamara.substack.com
Contextualizing Cryptography
What Is Cryptography For?
1123
Reposted by Sabine Oechsner
Clément Canonne @ccanonne.github.io · 02/06/2026
A list of principles put forth by mathematicians, for mathematicians and other researchers, regarding the use of AI in research. "Number #9 will surprise you!" leidendeclaration.ai
leidendeclaration.ai
Leiden Declaration on Artificial Intelligence and Mathematics
This declaration calls for action to address the challenges posed by the use of artificial intelligence within mathematics research.
02711
Reposted by Sabine Oechsner
Clément Canonne @ccanonne.github.io · 01/06/2026
And the website with details and registration form is up! sites.google.com/view/sydney-... Join us on July 22–24 at #USyd, in the @sydneycompsci.bsky.social, for a 3-day (free) intensive winter school on Interactive Proofs and the PCP Theorem! [Remote participation possible]
sites.google.com
Sydney TCS Winter School 2026
📅 July 22—24, 2026 🌏 Sydney (Australia)
2127
Reposted by Sabine Oechsner
Clément Canonne @ccanonne.github.io · 31/05/2026
Teaser: a colleague (Sasha Rubin) and I are planning a 3-day (free) "intensive Winter school" at #USyd on computational complexity: specifically, interactive proofs (IP=PSPACE) and the PCP theorem. July 22-24! I don't know how many people here are nearby and keen, but if you are: please do join!
1235
Reposted by Sabine Oechsner
Pavel @spavel.bsky.social · 30/05/2026
Thinking about why women might not want to use a product that has forced itself into every software interface to confidently shout things that are wrong
6070211616
Reposted by Sabine Oechsner
Matthew Green @matthewdgreen.bsky.social · 29/05/2026
Last week I discovered that ChatGPT and Claude will send you their “encrypted raw reasoning” and of course I immediately wasted a weekend trying to do something bad with it. What I got for my trouble was this blog post: blog.cryptographyengineering.com/2026/05/29/f...
blog.cryptographyengineering.com
Fooling around with encrypted reasoning blobs
This is a quick post I wanted to write about a “hobby project” I spent a weekend on. It has little to do with real cryptography, and mostly doesn’t expose a particularly exciting …
47824
Reposted by Sabine Oechsner
Real World Crypto Symposium @rwc.iacr.org · 28/05/2026
The Call for Contributed Talks for the 2027 edition of the Real World Crypto Symposium 2027 is now open. If you’ve built, deployed, broken, measured, migrated, or learned something the community should hear about, submit it. rwc.iacr.org/2027/contrib...
rwc.iacr.org
RWC 2027 call for papers
Real World Crypto Symposium
097
Reposted by Sabine Oechsner
Andrea Lathrop @cabernet.bsky.social · 26/05/2026
Cross-posting this from Twitter, because I like it: (by @littmath.bsky.social)
23510
Reposted by Sabine Oechsner
Dr. Michelle Fullwood @michelleful.bsky.social · 23/05/2026
I'm making a puzzle game where you discover German for yourself, starting from shared etymology and cultural knowledge. It's called German Is ~~Awful~~ Easy and the first five levels are up! Feedback welcome! michellefullwood.com/languages/ge... #puzzles #etymology #LearnGerman
Screenshot of the puzzle game "German is Awful, I mean, Easy", Level 1. On-screen puzzle shows the German words "Salz und Pfeffer" and the player is being asked to translate them for 10 points. Also present are a "Hint" button for -3 points and a "Reveal Letter" button for -3 points.
55911
Reposted by Sabine Oechsner
Gro-Tsen @gro-tsen.bsky.social · 23/05/2026
Very insightful short essay by Petra Schwer ( mathstodon.xyz/@PetraSchwer ): ‘The meaning of doing mathematics’ “(Can AI solve all math? What do we actually mean by doing mathematics? How do we communicate mathematics? What is mathematics beyond problem solving?)” arxiv.org/abs/2509.15998
arxiv.org
The meaning of doing mathematics
Can AI solve all math? What do we actually mean by doing mathematics? How do we communicate mathematics? What is mathematics beyond problem solving? This essay is my attempt to answer these question...
22813
Reposted by Sabine Oechsner
Tianxin Tang @koptxin.bsky.social · 22/05/2026
For anyone interested in being a tadpole reviewer (interesting concept, suitable for PhD students and early post-docs) for PETS 2027, you can submit an application using the following link: cryptpad.fr/form/#/2/for.... The PC application form can also be found on the website.
111
Reposted by Sabine Oechsner
Nalini Joshi @monsoon0.bsky.social · 21/05/2026
You may find the comments by Melanie Matchett Wood on the discovery of a counter example to Erdős’ Unit Distance Conjecture as interesting as I did 👇🏼(see previous post for a link)
A screenshot of p.17 of the paper available at https://cdn.openai.com/pdf/74c24085-19b0-4534-9c90-465b8e29ad73/unit-distance-remarks.pdf
27818
Reposted by Sabine Oechsner
Clément Canonne @ccanonne.github.io · 21/05/2026
The OpenAI breakthrough on the unit distance problem seems genuinely impressive to my semi-layman eye. (It is!) One possible takeaway, though, is that if you throw an incredible amount of money and resources at focused research, there WILL be impressive progress. I wish we tried that, too.
1517
Reposted by Sabine Oechsner
Mathy Vanhoef @vanhoefm.bsky.social · 19/05/2026
Nominate yourself to help review papers for USENIX Security 2027! sec-rms.com/submit-appli... (or rms.swag.cispa.de/submit-appli... ). Deadline: May 28, 2026. We're looking for both senior and junior people. See Andrei Sabelfeld's LinkedIn post for more info: www.linkedin.com/feed/update/...
sec-rms.com
Signal PC interest - USENIX Security Symposium
025
Reposted by Sabine Oechsner
Aram Zucker-Scharff @chronotope.aramzs.xyz · 11/05/2026
I think the screenshoted take is insane. If a mathematician discovered something with Matlab, if a scientist uses an algorithm, if a designer uses Adobe, if anything like that, the work belongs to the user. But big tech companies have been trying to claim the work of their users for a decade now.
5306
Reposted by Sabine Oechsner
Rasmus Pagh @rasmuspagh.net · 11/05/2026
Join us June 11-12 for a workshop on Differential Privacy and Unlearning in Machine Learning at University of Copenhagen! The workshop will feature tutorials, three great invited speakers (@grahamrc.bsky.social, @ahonkela.bsky.social and @koloskova.bsky.social), as well as contributed talks.
164
Sabine Oechsner @proofnerd.bsky.social · 10/05/2026
Fascinated by this M.C. Escher-esque suitcase on the Charles de Gaulle Airport website
An AI slop picture of suitcases at an airport.
030
Reposted by Sabine Oechsner
Doreen Riepel @doreenriepel.bsky.social · 08/05/2026
Join us tomorrow for ProTeCS, one of Eurocrypt’s affiliated events! We are thankful to have two amazing invited speakers, Bart Mennink and Mike Rosulek! We are also happy to have seven contributed talks from the community. Check out our full program here: protecs-workshop.gitlab.io/program
protecs-workshop.gitlab.io
Program
Workshop on Proofs and Proof Techniques for Cryptographic Security. Affiliated with Eurocrypt 2026.
163
Reposted by Sabine Oechsner
Nils Fleischhacker @cryptomaeher.bsky.social · 07/05/2026
My time at RUB is coming to an end and I'm looking for an industry position. Primarily looking for remote or Rhine-Ruhr area positions, but will consider any exceptional offers. So if you're looking to hire a cryptographer to work on cryptographic protocols, or related areas, maybe we should talk!
158
Reposted by Sabine Oechsner
National Trust @nationaltrust.org.uk · 03/05/2026
We have an *extremely* important announcement to make. From Wednesday, we will be launching our puffin live cam, coming to you from the Farne Islands. So you can watch puffins all day long. In celebration, please enjoy this clip of puffins being really busy for 39 seconds straight.
7872012473
Reposted by Sabine Oechsner
Clément Canonne @ccanonne.github.io · 30/04/2026
SIGACT is providing travel support to attend #STOC2026! "These travel awards are for students who are short on funds and are intended to help cover their registration, travel, and accommodation expenses." Deadline: ⏰ May 13 acm-stoc.org/stoc2026/tra...
acm-stoc.org
STOC 2026 - 58th ACM Symposium on Theory of Computing
0106
Reposted by Sabine Oechsner
Sabine Oechsner @proofnerd.bsky.social · 17/04/2026
I'm looking for a PhD student to work with me on formal verification for cryptographic protocols. This is a 4-year position at VU Amsterdam, co-supervised with Kristina Sojakova. Send me an email if you want to know more!
11013
Reposted by Sabine Oechsner
Aravind (Sri AravindaKrishnan Thyagarajan) @aravind16coiner.bsky.social · 27/04/2026
📢 📢 📢 🚨 I am looking for two PhD students to hire in post quantum cryptography. Exciting opportunity to work at University of Sydney @sydneycompsci.bsky.social and the theory/crypto groups here. Do share with your students and contacts. #hiring #phd #pqc #cryptography 🔗 iacr.org/jobs/item/4199
iacr.org
Two PhD Positions in Post-Quantum Cryptography (PQC)
023
Reposted by Sabine Oechsner
Mark Riedl @markriedl.bsky.social · 22/04/2026
Fantastic (long) piece on what AU means to mathematics (and what mathematics is) So many insights. The first begins why so may people in AI research are getting obsessed with “taste”. davidbessis.substack.com/p/the-fall-o...
davidbessis.substack.com
The fall of the theorem economy
How AI could destroy mathematics and barely touch it
14010
Sabine Oechsner @proofnerd.bsky.social · 17/04/2026
👀
Screenshot from the blog post:

Zero-knowledge systems are an incredible technology with many applications, but their use introduces a different set of risks than traditional approaches. They aren’t a magic wand that eliminates trust; instead, they redistribute trust from an original domain, such as the opinions of scientific experts, to trust in programming languages, compilers, proof systems, and cryptography experts. There are many frontiers that are considering the benefits of zero-knowledge, including electronic voting and age verification, but it’s also critical to consider the risks and make plans for what happens when this technology fails.
0276
Reposted by Sabine Oechsner
Fredrik Dahlgren @fegge.bsky.social · 17/04/2026
Two weeks ago, Google published a paper proving in zero-knowledge that they had an efficient implementation of Shor's algorithm. Today, Trail of Bits can prove that we have an even better implementation which beats Google's on all metrics! 🫢 blog.trailofbits.com/2026/04/17/w...
A table listing total operations, number of qubits, and Toffoli-gate count for Google's low-gate and low-qubit implementations, and Trail of Bits' implementation. The Trail of Bits implementation beats Google's on every metric.
18230