Carsten Baum
@crypto_carsten
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Associate Professor in Cryptography at @DTU_Compute in Copenhagen, Denmark. Any opinions are entirely mine.
Copenhagen, Denmark
Joined December 2020
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Hiring news!
Are you interested in doing a PhD or Postdoc with me in Post-Quantum or Threshold Cryptography? Then join our growing Cryptography group at
@DTU_Compute
in Denmark!
PhD call:
Postdoc call:
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German government signed a contract with IBM to design a Corona vaccine passport system.
Using 5 Blockchains.
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US academics trying to get European academics to do anything during summer break.
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This looks serious. Damn serious. Some lattice expert can say something about it?
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Since Twitter is full of academics who brag about their successes, here's my week:
1 grant rejected
2 papers rejected
First ever invitation for a conference keynote, only to have that withdrawn a little later
I don't want pity, only to say: it can suck in times, for all of us.
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The bad thing about being tenured starting April 1st is that nobody will believe you 😐
But still: from today on this Carsten is an Associate Professor at
@DTU_Compute
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Finally allowed to share this: I've been very lucky to have been awarded a Villum Young Investigator starting grant to research post-quantum threshold cryptography. Two PhD students and a Postdoc will be hired as part of the project over the next 5 years.
22 research talents from the technical and natural sciences receives a combined total of DKK 126 million through our Villum Young Investigator Programme. Their research areas range from plants to stellar streams
#VillumYoungInvestigators
#dkforsk
#dkvid
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Dropping new results on eprint is one thing - but dropping the most epic rap video about a cryptography result is just beyond everything I've seen before.
Kudos to the authors :)
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Job-related news:
Today is my last full-time day as an Assistant Professor at
@AarhusCrypto
. Starting next Monday, I will join DTU Copenhagen's DIGISEC group at
@DTU_Compute
to work alongside Christian Majenz
@cmajenz
and Tyge Tiessen.
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This pun is so bad, I had to translate it:
If your induction stove can cook n dishes, then it can also cook n+1 dishes.
Wenn du mit einem Induktionsherd n Gerichte kochen kannst, dann kannst du damit auch n+1 Gerichte kochen.
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Since lots of people seem to migrate from Whatsapp to Telegram:
1. Telegram chats are, per default, not encrypted.
2. Unencrypted Telegram messages are stored on Telegram's servers.
3. Telegram group chats are not encrypted.
Want to stay secure and free of Facebook? Use Signal.
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Cryptographers reading "the security of our product relies on a novel, secret and patented hash function and/or encryption algorithm"
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You have seen Picnic, BBQ and Banquet. Now get ready for FAEST!
TL;DR: FAEST is highly efficient AES-based digital signature scheme. It has <1ms sign/verify with 6.3KB signatures (fast mode) or 8ms sign/verify with 5KB (small mode) for 128bit security.
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Maybe I'm wrong with this assumption, but for most researchers in the world Saturday and/or Sunday are their weekend. Where you relax and spend time with friends and family.
Why do we continue to foster bad habits by putting deadlines on Sundays? Why not Wednesday?
The CCS deadline is coming very soon (January 28th), and we are looking forward to your awesome submissions!
Submission website:
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I've been asked to give a short talk about how ML can benefit from blockchains.
I think one slide is sufficient for the talk.
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Our Mac'n'Cheese ZK proof system () has been accepted at CRYPTO 2021🥳 Thanks to my great co-authors
@schollster
, Alex J. Malozemoff & Marc Rosen.
I guess it's clear what type of food fits the occasion😀
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Our new designated-verifier ZK paper for proofs over rings mod 2^k is out!
The motivation for this work is that operations mod 2^k, are the standard data format on a CPU. That's what CS people love to use - encoding programs over large fields or as bits can be cumbersome. 1/n
#ePrint
Moz$\mathbb{Z}_{2^k}$arella: Efficient Vector-OLE and Zero-Knowledge Proofs Over $\mathbb{Z}_{2^k}$: C Baum, L Braun, A Munch-Hansen, P Scholl
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While others are at Real World Crypto, I'm currently practicing Ideal World CRYPTO.
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Almost every cryptography researcher between today and February 16th.
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Spread the word: we are organizing a Summer School on Privacy-Preserving Machine Learning in early August in Copenhagen. We got a great line-up of speakers for you.
More info and registration here:
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Two weeks before the deadline: this time we'll get everything done way ahead of time!
Two hours before deadline: \vspace{-5cm}
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@gepardtatze
Ach komm Tatze, bei dir im Keller arbeitest du sicher schon am Aufbau einer Produktionslinie :)
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On the positive side, both my FC () and PKC () submissions got accepted!
On an even more positive note, my EC submission - just like good wine - was allowed to mature a bit more before being accepted elsewhere.
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I've been quite excited about this work and finally it is public on eprint (and accepted at CRYPTO 2023):
On a very high level, our work allows to make recent designated-verifier based Zero Knowledge protocols publicly verifiable. 1/3
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Off for 4 months of parental leave.
So long, and thanks for all the diapers!
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The legendary
@deescuderoo
finishes his PhD defense with a song.
Congrats Dr. Daniel and all the best. You will be missed!
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has finally turned into an honest website, describing what the IACR is about :)
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I wonder if someone tried to base cryptography on the hardness of finding secure parameter sets for efficient lattice-based cryptography.
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This is what academia should be :)
Avi Wigderson wins the Turing Award 🏆
Others speak of Avi's math and CS genius, but here's a glimpse of his character ❤️
@TheOfficialACM
#ACMTuringAward
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Say what you want about Belgium, but having to wear fancy robes for a PhD defense is something we should all copy.
Also
@SmartCryptology
without a Hawaii shirt.
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And so I got invited to publish my work in a predatory journal on "Trends in Development and Use of Fermented Dairy Products".
I feel like our cheese puns went too far...
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It's great that this paper about practically proving security weaknesses in software in zero-knowledge without revealing the bug is finally out:
It's not a paper of me, but of colleagues I collaborate with on a DARPA project.
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The list of accepted talks for TPMPC 2022 is now online. So many cool things you can learn about if you come to Aarhus in June :)
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Good news everyone: Our Feta Distributed Verifier-Zero Knowledge proof system was accepted at
@acm_ccs
2022. This is joint work with the fantastic Robin Jadoul, Emmanuela Orsini,
@schollster
and
@SmartCryptology
. A preliminary version can be found here .
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@LindellYehuda
@AlexMartin
@rossjanderson
@sjmurdoch
@pwnallthethings
One more thing which people don't have on their radar just yet: since Apple controls their App store tightly, using their system might become mandatory for all messaging apps on Apple devices.
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When the paper finally fits the page-limit of a conference.
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Great invited talk by
@LindellYehuda
about MPC's way from theory to practice and lessons learned about building cryptography-based products.
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@KBoudgoust
from
@AarhusCrypto
presenting her work that earned her a "Best Early Career Paper" award at CRYPTO 2022. Congrats!
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Picnic is for me one of the coolest signature schemes there is. Unfortunately, it uses a less-well-tested block cipher.
So we adapted it to AES and it is quite efficient too 🙂
#ePrint
Banquet: Short and Fast Signatures from AES: C Baum, CDdS Guilhem, D Kales, E Orsini, P Scholl, G Zaverucha
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@ennolenze
Falls es dich beruhigt: wir Professoren bekommen den Stundenplan teilweise auch erst zur gleichen Zeit...
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I'm very happy to share that our recent improvement to VOLE-in-the-head/FAEST is now online on eprint: .
This is joint work with
@WardBeullens
, Shibam Mukherjee,
@EmmanuelaOrsini
,
@sebastinas_
, Christian Rechberger, Lance Roy and
@schollster
.
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Although I'm a bit sad thst my submission to PKC2022 was rejected I'm glad about having gotten one of the best and most constructive review that I ever got. The review process is not fully broken :)
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@chelseakomlo
Indeed.
RWC 2023: Here's all the new PQ crypto implementations!
CRYPTO 2023: Here's all the broken new PQ implementation
RWC 2024: Now we implemented it securely.
CRYPTO 2024: no
...
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On this day 5 years ago I was awarded a PhD in Computer Science.
Since then I made a lot of reviewers very angry who have in retrospect widely regarded it as a bad move by
@AarhusCrypto
.
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When explaining Secure Computation, always give an example adjusted to the audience.
Today: explaining PSI in Jerusalem next week.
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Idea: cryptography based on the hardness of making your newborn do something you want.
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Reviewer: "Isn't this already covered by the following work of Baum et al....?"
Me: "Seriously?"
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As math-oriented researchers we know: whatever the properties of the Delta-Covid19 variant is, the impact of the coming Epsilon variant can't be too large...
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First paper of 2022 - and we continue in the line of cheese-related work.
In this paper, we ask how you could specify and design zero-knowledge proofs towards multiple verifiers. This is somewhere between public verifiability (e.g. SNARKS) and designated-verifier proofs. 1/4
#ePrint
Feta: Efficient Threshold Designated-Verifier Zero-Knowledge Proofs: C Baum, R Jadoul, E Orsini, P Scholl, NP Smart
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Good morning from Pullach, Germany, where
@mkskeller
and me will teach students about MPC this week.
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Ladies and Gentlemen: Crypto now officially goes to Space :)
New joint work with
@akiratk0355
, Elena Pagnin and Bernardo David.
#ePrint
CaSCaDE: (Time-Based) Cryptography from Space Communications DElay: C Baum, B David, E Pagnin, A Takahashi
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Congrats to my better half for being a tenured professor 🎉
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Clearly: Isogenies, LWE, Indistinguishability Obfuscation, Diffie-Hellman.
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On the 2.2 of 22 I got 2 rejections for Eurocrypt.
At least a beautiful pattern.
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Are you (or do you know) a Master student who is looking for a PhD position in cryptography, starting early next year? Then consider applying at
@DTU_Compute
!
You will work on threshold and post-quantum cryptography in the beautiful Copenhagen region of Denmark.
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TPMPC 2022 is fun as always :)
This week,
@AarhusCrypto
is hosting the 2022 Theory and Practice of Multi-Party Computation Workshops at the department - gathering experts from all over the world. Unable to attend? Follow the live stream ➡️
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I would have expected a "this destroyes all Ring-LWE-based cryptography" in the abstract.
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Yay for
@DTU_Compute
's cryptography team! We got two papers accepted at this year's
@IACRcrypto
conference :)
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I'm happy that this paper is finally on eprint .
In it, we construct the first MPC protocol with identifiable abort that could plausibly be implemented. It uses a PCG-based preprocessing with a BDOZ online phase. The hard work is the identifiable abort.
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Asiacrypt 0 out of 1. Congrats to everyone who got a paper in!
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LinkedIn Jobs is fun. It just told me I'm very qualified to do a Postdoc at DTU advised by...me :)
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Really love this honesty about issues with one's own work and how they can be fixed.
As a community, we need a mechanism for this that is better than Twitter though, given the ramifications of bugs or underspecification.
Also: no, this doesn't need a Blockchain.
Announcing a major update to
(with
@luca_defeo
and
@meshcollider
)
There was an issue with the proof of computational zero knowledge for all sigma protocols in the previous version, due to our mis-understanding of the definition. 1/2
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Yay, seems like LWE is not so dead after all.
For now.
Is lattice-based cryptography still (potentially) post-quantum now? 🥳
Update to
#eprint555
by Yilei Chen
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Come to Copenhagen and be my new PhD student. I promise lots of Crypto and bad puns.
#Job
PhD Scholarship in Cryptography: Technical University of Denmark, Section for Cybersecurity Engineering
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Off to Graz for my first time as a PhD opponent.
This feels exciting :)
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In a controversial 6-3 decision, the US Supreme Court has ruled that you should just make up your own cryptography algorithms and implement them yourself.
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I wish there was a book about all the cool stuff Donald Beaver invented for MPC.
Then whenever I re-invent a cool trick and think "this must be known to the community" I could just go \cite{the_beaver}.
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Please RT if applicable:
The Aarhus Crypto group
@AarhusCrypto
is looking for Postdocs in Distributed Ledger and general Cryptographic Protocols for work on our Concordium and SecureDNA projects.
More info can be found here:
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We spent some time to make a comprehensive list of use of MPC (and some other PETs) in classical finance and Defi.
With
@digi_james
, Bernardo and Tore.
#ePrint
SoK: Privacy-Enhancing Technologies in Finance: C Baum, JHy Chiang, B David, TK Frederiksen
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I am in
@acm_ccs
town but will not really be at the conference, as I am still on parental leave. I plan to show up at the venue Wednesday after lunch. If you see me walking around with a baby - just say hi :)
Particularly if you consider a Postdoc or PhD in cryptography in DK :)
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Dear authors, we are delighted to inform you that you have a submission to CRYPTO this year.
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@boazbaraktcs
@matthew_d_green
I also recommend following
@SmartCryptology
on this .
That being said, the website background gives me a headache.
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Really excited to see ORAM being used by Signal. Now let's do some more work to get rid of SGX :)
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Americans being outraged when Europeans treat them the way they treat Europeans.
I feel like this is something that should be a much bigger story than it is: Starting next year, American passport-holders won't have visa-free access to Europe.
Instead, you'll have to pay 7 Euros and wait *14 days* for an entry visa to be processed.
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3K
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Pre-covid in-person presentation: let me talk 1h about this topic without getting stuff wrong.
Me, recording a video about a paper now:
Restarting >5 times because I keep forgetting my name.
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My PhD student is outperforming me at awful puns and I have never been prouder.
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We've now reached the point where computer scientists have to pay nearly $2000 to get their work published at ACM venues.
IACR shows that you can get high quality publication venues with decent review. ACM CCS is now a cash grab.
I wonder how it will affect
@TheOfficialACM
conferences when they charge $1300/1800 to authors in order to publish a paper in 2026. Many authors will be unaware of it because of the tax their institutions are already paying.
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Months before the deadline, when sketching the paper: "ah, the proof trivially follows"
Week before deadline, when writing the proof: "oh boy, was I naive"
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New paper alert. This came out of
@schollster
and me being asked to write a survey on VOLE-based ZK. So we invited Samuel Dittmer and
@wangxiao1254
to join us, because they (among many others) have also contributed a lot to research in the area.
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Got a late review from a conference and have 3 days to respond to the review. Review was sent out Friday evening.
Stop forcing people to work over the weekend!
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Never have we cryptographers had such a reliable source of unpredictable, unbiasable randomness as the flight situation in Europe in the Summer of 2022.
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"our work solves the problem in a novel and interesting way"
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@claudiorlandi
is finally full professor at
@csaudk
. Well-deserved, ProfessOrlandi :)
Congrats Professor
@claudiorlandi
🎉 Read more about Claudios journey from Erasmus student to professor at the department ➡
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We've officially gotten to the point where:
1. All authors agree that our cryptographic protocol is secure because it can be proven so.
2. All authors agree that our cryptographic protocol is too complicated to fully understand.
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The EU is attempting to remove privacy of all web traffic in Europe, by giving every EU government the capability to surveil all its citizens...
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More often than not, we should add the following phrase to all papers about cryptographic protocols:
Beware of bugs in the above protocol; we have only proved it secure, not implemented it.
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Watching this peer review vs. Arxiv debate from my cryptography point of view is fun.
What our community does and largely believes is right: have both! Preprints are important, in particular for timestamping. But peer review is important for sanity checking!
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As a cryptographer I have a weakness for works that break stuff. Hence I really enjoyed the lecture by
@realyangzhang
about membership attacks on models. Great food for thought!
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Sensible thread that summarizes what I think many in the cryptography community think right now.
I implore you, don’t give a mundane FOIA lawsuit more attention than it deserves.
It’s 2022, we should all be inoculated against people “just asking questions” and spinning loose facts into conspiracy theories.
Ask yourself if you’re being sold a story on emotions and why.
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@ennolenze
Finds geil wie man in Deutschland Datenschutz vorschiebt (aber Payback-Karte im Portemonnaie) nur um Steuerhinterziehung betreiben zu können.
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Eurocrypt 2021. Where the presentations are shorter than Rump Session talks.
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