Quasipolynomial Cryptanalysis of the McEliece Cryptosystem (or: PIR Meets McEliece) (Ashrujit Ghoshal, Yuval Ishai, Aayush Jain, Nuozhou Sun) ia.cr/2026/1630
Janno Siim
@jannosiim.bsky.social
Lecturer in Cryptography at the University of Tartu. From Estonia. ZK proofs, SNARKs, security assumptions. Homepage: https://sites.google.com/view/jannosiim
This is a very cool and exciting discovery by Claude Mythos! It found a serious 𝒎𝒂𝒕𝒉𝒆𝒎𝒂𝒕𝒊𝒄𝒂𝒍 attack on the post-quantum signature scheme HAWK, an "on-ramp" candidate for potential NIST standardization. www.anthropic.com/research/dis...
Discovering cryptographic weaknesses with Claude
Anthropic researchers find weaknesses in cryptographic algorithms with Claude Mythos Preview
anthropic.com
TOMORROW AT 12:00 is the final vote on Chat Control 1.0. An absolute majority of 361 MEPs is needed to stop it! This is the works of EP President Roberta Metsola who is forcing through the vote on Chat Control 1.0 despite the plenary already rejecting it. Take action now! fightchatcontrol.eu
I already posted earlier links, here's a very timely quanta summary! www.quantamagazine.org/new-advances...
New Advances Bring the Era of Quantum Computers Closer Than Ever | Quanta Magazine
Two research groups say they have significantly reduced the amount of qubits and time required to crack common online security technologies.
quantamagazine.org
In less than three hours from now! Send e-mails and call your MEPs (proposed call script is available on the website for each MEP) via fightchatcontrol.eu !
Fight Chat Control@fightchatcontrol.bsky.social · 5mo agoThe European Parliament is voting THURSDAY 26th at 11:00 on Chat Control. The Commission, Council, multiple tech giants, the Conservatives (EPP), and several MEPs from S&D and Renew stand united in favouring indiscriminate mass surveillance. Tell them NO: fightchatcontrol.eu
🚨 The Conservatives (EPP) are attempting to force a new vote on Thursday (26th), seeking to *reverse* Parliament's NO on indiscriminate scanning. This is a direct attack on democracy and blatant disregard for your right to privacy. No means no. Take action now: fightchatcontrol.eu
The EU seems to be going in the right direction when it comes to mass message scanning. Unfortunately, the fact that this vote was necessary proves that we’re still in the dark timeline. cyberinsider.com/eu-votes-to-...
EU votes to restrict mass scanning of people’s private messages
The European Parliament has voted to curb untargeted mass scanning of private communications in the EU, in a key 'Chat Control' development.
cyberinsider.com
UPDATE: The European Parliament voted today to *end* untargeted mass scanning of private communications, firmly rejecting the error-prone and unconstitutional surveillance practices of recent years! Next: trilogue negotiations w/ Commission and Council.
About page limits. Why do CS conferences have them? If you look at the length of papers posted to eprint.iacr.org, 96% of them are at most 75 pages. Seems like we should just publish them instead of jumping through hoops to fit the old world of paper.
Second Eurocrypt paper Cyclo: Lightweight Lattice-based Folding via Partial Range Checks (Garreta, Lipmaa, Luhaäär, Osadnik) eprint.iacr.org/2026/359
Cyclo: Lightweight Lattice-based Folding via Partial Range Checks
Folding is a powerful technique for constructing efficient succinct proof systems, especially for computations that are expressed in a streaming fashion. In this work, we present Cyclo, a new lattic...
eprint.iacr.org
I'll spam on this platform as well. Our Eurocrypt paper with @helger.bsky.social Roberto Parisella, and Erki Külaots is now live eprint.iacr.org/2026/326. It's for all the SNARK lovers. We propose a nice framework for constructing tightly secure SNARKs from special-sound polynomial IOPs.
Special Soundness and Binding Properties: A Framework for Tightly Secure zk-SNARKs
Interactive arguments often combine polynomial IOPs with polynomials commitment schemes (PCSs). Frequently, the interactive argument is proven to be knowledge sound, but this incurs a high securi...
eprint.iacr.org
SNARGs for NP and Non-Signaling PCPs, Revisited (Lalita Devadas, Samuel B. Hopkins, Yael Tauman Kalai, Pravesh K. Kothari, Alex Lombardi, Surya Mathialagan) ia.cr/2026/006
![Abstract. We revisit the question of whether it is possible to build succinct non-interactive arguments (SNARGs) for all of NP under standard assumptions using non-signaling probabilistically checkable proofs [Kalai-Raz-Rothblum, STOC’ 14]. In particular, we observe that using exponential-length PCPs appears to circumvent all of the existing barriers.
For our main result, we give a candidate non-adaptive SNARG for NP and prove its soundness under:
- the learning with errors assumption (or other standard assumptions such as bilinear maps), and
- a mathematical conjecture about multivariate polynomials over the reals.
In more detail, our conjecture is an upper bound on the minimum total coefficient size of Nullstellensatz proofs (Potechin-Zhang, ICALP 2024) of membership in a concrete polynomial ideal. We emphasize that this is not a cryptographic assumption or any form of computational hardness assumption.
Of particular interest is the fact that our security analysis makes non-black-box use of the SNARG adversary, circumventing the black-box barrier of Gentry and Wichs (STOC ’11). This gives a blueprint for constructing SNARGs for NP that is not subject to the Gentry-Wichs barrier.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:fwa55bujvdrwlwlwgqmmxmuf/bafkreiebzoc3ibat7fphuhytkkbm2wsivcmvrfb2u2dtnddbzh45lnt56e)
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
csa-scientist-open-letter.org
Really happy to have Jens Groth visiting us in Tartu and giving a seminar on ZK, zkVMs, and AI on Tuesday
![Abstract. A zero-knowledge proof demonstrates that a fact (like that a Sudoku puzzle has a solution) is true while, counterintuitively, revealing nothing else (like what the solution actually is). This remarkable guarantee is extremely useful in cryptographic applications, but it comes at a cost. A classical impossibility result by Goldreich and Oren [J. Cryptol. ’94] shows that zero-knowledge proofs must necessarily sacrifice basic properties of traditional mathematical proofs — namely perfect soundness (that no proof of a false statement exists) and non-interactivity (that a proof can be transmitted in a single message).
Contrary to this impossibility, we show that zero-knowledge with perfect soundness and no interaction is effectively possible. We do so by defining and constructing a powerful new relaxation of zero-knowledge. Intuitively, while the classical zero-knowledge definition requires that an object called a simulator actually exists, our new definition only requires that one cannot rule out that a simulator exists (in a particular logical sense). Using this, we show that every falsifiable security property of (classical) zero-knowledge can be achieved with no interaction, no setup, and perfect soundness. This enables us to remove interaction and setup from (classical) zero-knowledge in essentially all of its applications in the literature, at the relatively mild cost that such applications now have security that is “game-based” instead of “simulation-based.”
Our construction builds on the work of Kuykendall and Zhandry [TCC ’20] and relies on two central, longstanding, and well-studied assumptions that we show are also necessary. The first is the existence of non-interactive witness indistinguishable proofs, which follows from standard assumptions in cryptography. The second is Krajícek and Pudlák’s 1989 conjecture that no optimal proof system exists. This is one of the main conjectures in the field of proof complexity and is the natural finitistic analogue of the impossibility of Hilbert’s second problem (and, hence, also Gödel’s incompleteness theorem). Our high-level idea is to use these assumptions to construct a prover and verifier where no simulator exists, but the non-existence of a simulator is independent (in the logical sense of unprovability) of an arbitrarily strong logical system. One such logical system is the standard axioms of mathematics: ZFC.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:fwa55bujvdrwlwlwgqmmxmuf/bafkreiflntzdprcpqm2vxfmwhx6gke7sa2bzx2oc2ju7zrjnqeqymx3nh4)
Springer just sent an "Urgent" email that many authors from Crypto 2025 (all from ZK community) have broken references provided as "?" in their camera-ready version:
Our paper with Roberto Parisella and Maiara Bollauf was accepted to CiC. We extend DL <=> CDH reduction by den Boer and Maurer. In particular, we show that in BLS12-381 n-PDL (Power DL) is equivalent to n-Diffie-Hellman exponent assumption.
ePrint Updates@eprint.ing.bot · last yr.Revisiting Discrete Logarithm Reductions (Maiara F. Bollauf, Roberto Parisella, Janno Siim) ia.cr/2025/1079
![Abstract. A reduction showing that the hardness of the discrete logarithm (DL) assumption implies the hardness of the computational Diffie-Hellman (CDH) assumption in groups of order p, where p − 1 is smooth, was first presented by den Boer [Crypto, 88].} We also consider groups of prime order p, where p − 1 is somewhat smooth (say, every prime q that divides p − 1 is less than 2¹⁰⁰). Several practically relevant groups satisfy this condition. 1. We present a concretely efficient version of the reduction for such groups. In particular, among practically relevant groups, we obtain the most efficient and tightest reduction in the literature for BLS12-381, showing that DL = CDH. 2. By generalizing the reduction, we show that in these groups the n-Power DL (n-PDL) assumption implies n-Diffie-Hellman Exponent (n-DHE) assumption, where n is polynomial in the security parameter. On the negative side, we show there is no generic reduction, which could demonstrate that n-PDL implies the n-Generalized Diffie-Hellman Exponent (n-GDHE) assumption. This is in stark contrast with the algebraic group model, where this implication holds.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:fwa55bujvdrwlwlwgqmmxmuf/bafkreiezbnvidm7exhiiqdi74nhd7zfkdu25rzyl2kkwgwvotqvn2jaduu)
"Trump scraps Biden software security, AI, post-quantum encryption efforts in new executive order" by @ericjgeller.com www.cybersecuritydive.com/news/trump-c... (updated EO 14144 text using Gemini 2.5 Pro here: docs.google.com/document/d/1... )
Trump scraps Biden software security, AI, post-quantum encryption efforts in new executive order
The White House accused the Biden administration of trying to “sneak problematic and distracting issues into cybersecurity policy.”
cybersecuritydive.com
New accepted paper at Crypto 2025: "On Knowledge-Soundness of Plonk in ROM from Falsifiable Assumptions" (Helger Lipmaa, Roberto Parisella, Janno Siim), with ex-students Roberto and @jannosiim.bsky.social (Janno is also now a colleague)
In other news, Google is deploying age/ID verification based on ZK proofs. blog.google/products/goo...
It’s now easier to prove age and identity with Google Wallet
Learn more about new Google Wallet updates, including new ways to use your digital ID for age and identity verification.
blog.google
Europe's most famous technology law, the GDPR, is next on the hit list as the EU pushes ahead with its regulatory killing spree to slash laws it reckons are weighing down its businesses.
Europe’s GDPR privacy law is headed for red tape bonfire within ‘weeks’
Long seen as untouchable in Brussels, the GDPR is next on the list of the EU’s crusade against overregulation.
politico.eu
Join us in Tartu to work on SNARKs and ZK proofs. 👇 We intend to build a strong ZK research group here + I think it's a really cool place to live and work: virtualtour.ut.ee/en/84-univer...
This link will take you to a page that’s not on LinkedIn
lnkd.in
Helger Lipmaa@helger.bsky.social · last yr.Our group in Tartu (me and @jannosiim.bsky.social and some PhD students) have additional openings for a postdoc and a PhD student; see crypto.cs.ut.ee/Main/OpenPos... (iacr.org/jobs link will hopefully be up in a few days). Apply by email to me
Our group in Tartu (me and @jannosiim.bsky.social and some PhD students) have additional openings for a postdoc and a PhD student; see crypto.cs.ut.ee/Main/OpenPos... (iacr.org/jobs link will hopefully be up in a few days). Apply by email to me
Cryptography Research Group
crypto.cs.ut.ee
The list of accepted talks for ProTeCS 2025 is now online. We are looking forward to exciting talks about cryptographic proofs and proof techniques. Thanks to everyone who submitted a proposal! protecs-workshop.gitlab.io/accepted
We have extended the submission deadline for the International Workshop on Foundations and Applications of Privacy-Enhancing Cryptography (PrivCrypt) by two weeks to April 4, 2025, AoE. Please help spread the word and consider submitting your work to join us in Munich in Summer 😎
Daniel Slamanig@drl3c7er.bsky.social · 2y agoWe are organising the International Workshop on Foundations and Applications of Privacy-Enhancing Cryptography (PrivCrypt) - co-located with ACNS 2025 end of June in beautiful Munich. Submission deadline is March 21, 2025 (AoE). Please help spread the word! 🙏 privcryptworkshop.github.io