Michele Orrù
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tumbolia.bsky.social
Michele Orrù
@tumbolia.bsky.social
320 followers 120 following 71 posts
A curious child. https://michele.orru.net
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tumbolia.bsky.social
the new dragon book cover is incredible
October 17, 2025 at 6:08 AM
tumbolia.bsky.social
Got invited to @college-de-france.fr for a seminar about zero-knowledge and online anonymity! 🎉🎉🎉

www.college-de-france.fr/fr/agenda/se...
September 23, 2025 at 11:33 AM
tumbolia.bsky.social
Thrilled to announce that my latest paper with Alessandro Chiesa has been accepted to TCC, the IACR conference on the theory of cryptography!
August 30, 2025 at 6:39 PM
tumbolia.bsky.social
I'll present my latest paper on anonymous credentials and designated-verifier kzg at ACM CCS 2025 in Taipei!
August 24, 2025 at 10:41 PM
Reposted by Michele Orrù
rt-saber.bsky.social
Phrack #72 release reveals TTPs, backdoors and targets of a Chinese/North Korean state actor mimicking Kimsuky

A copy of his workstation is available for all researchers to analyze!

Article: data.ddosecrets.com/APT%20Down%2...
Data dump: ddosecrets.com/article/apt-...
APT Down - The North Korea Files - Distributed Denial of Secrets
Approximately 9 GB of files exfiltrated from a North Korean threat actor's computer. The data is being released alongside Phrack, and South Korean victims were notified prior to publication. Resear...
ddosecrets.com
August 9, 2025 at 7:16 PM
Reposted by Michele Orrù
opalescentopal.bsky.social
With Tom Lehrer's passing, I suppose this is a moment to share the story of the prank he played on the National Security Agency, and how it went undiscovered for nearly 60 years.
July 27, 2025 at 9:01 PM
tumbolia.bsky.social
Yesterday, @cathie.bsky.social gave a great talk at @ietf.org 123 on the importance of standardizing Sigma protocols and our ongoing work toward a standard for zero-knowledge proofs! You can watch the talk here:
IETF 123: Crypto Forum (CFRG) 2025-07-24 15:00
YouTube video by IETF - Internet Engineering Task Force
www.youtube.com
July 26, 2025 at 3:30 AM
tumbolia.bsky.social
We updated our paper on Fiat-Shamir!

We now take a closer look at the gap between what symmetric cryptography has focused on for over 10 years (indifferentiability) and what is actually needed for the soundness of ZKPs and SNARKs (something stronger!).

eprint.iacr.org/2025/536
A Fiat–Shamir Transformation From Duplex Sponges
We analyze a variant of the Fiat–Shamir transformation based on an ideal permutation. The transformation relies on the popular duplex sponge paradigm, and minimizes the number of calls to the permutat...
eprint.iacr.org
July 15, 2025 at 6:08 AM
Reposted by Michele Orrù
eprint.ing.bot
On the Concrete Security of BBS/BBS+ Signatures (Rutchathon Chairattana-Apirom, Stefano Tessaro) ia.cr/2025/1093
Abstract. BBS/BBS+ signatures are the most promising solution to instantiate practical and lightweight anonymous credentials. They underlie standardization efforts by the W3C and the IRTF. Due to their potential for large scale deployment, it is paramount to understand their concrete security, but a number of questions have been left open by prior works. To this end, the security proofs by Au et al. (SCN ’06), Camenisch et al. (TRUST ’16), and Tessaro and Zhu (EUROCRYPT ’23) show reductions from q-SDH in groups of prime order p, where q is the number of issued signatures. However, these prior works left the possibility open that BBS/BBS+ is “even more secure” than what can be guaranteed by such proofs. Indeed, while the q-SDH assumption is subject to an attack that uses $O(\sqrt{p/q})$ group exponentiations (Cheon, EUROCRYPT ’06) for several choices of q, no attack with a similar complexity appears to affect either of BBS+ and “deterministic” BBS, for which the best known attacks amount to recovering the secret key by breaking the discrete logarithm problem. The assumption that this attack is best possible also seemingly justifies the choice of parameters in practice. Our result shows that this expectation is not true. We show new attacks against BBS+ and deterministic BBS which, after seeing q signatures, allow us to recover the secret key with the same complexity as solving the Θ(q)-Discrete Logarithm problem, which in turn is proportional to $O(\sqrt{p/q})$ for many choices of q. Further, we also extend the attack to a reduction showing that the security of BBS+ and deterministic BBS implies the Θ(q)-SDH assumption. Image showing part 2 of abstract.
June 12, 2025 at 12:26 PM
Reposted by Michele Orrù
cknabs.bsky.social
I'm happy to finally open-source lattirust, a library for lattice-based zero-knowledge/succinct arguments! Lattirust is somewhat like arkworks, but for lattices; and like lattigo, but for arguments.

➔ github.com/lattirust
lattirust
Lattice zero-knowledge/succinct arguments, and more - lattirust
github.com
May 20, 2025 at 2:55 PM
tumbolia.bsky.social
so there's two nexus that do AI now, one is the world library and the other the world computer. here's the old one github.com/nexus-stc/stc
GitHub - nexus-stc/stc: Distributed free search engine and AI tools that grant access to knowledge
Distributed free search engine and AI tools that grant access to knowledge - nexus-stc/stc
github.com
May 10, 2025 at 8:42 PM
tumbolia.bsky.social
Our paper "Beyond the Circuit" was accepted at IACR's Communications in Cryptology!
It contains a few simple protocols for simplifying foreign arithmetic in zero-knowledge proofs. Formally we introduce "Σ-reductions", a mix of "Σ-protocols" and "reductions of knowledge".

🗞️ cic.iacr.org/p/2/1/23/pdf
April 11, 2025 at 12:25 PM
Reposted by Michele Orrù
ooni.org
How to protect the OONI dataset from attacks, while preserving the privacy of OONI Probe users?

In our latest blog post, we outline some of the key requirements for OONI's anonymous credential system: ooni.org/post/2025-re...

#AnonymousCredentials #ooniprobe #ooni
March 24, 2025 at 8:44 PM
tumbolia.bsky.social
Tomorrow I will venture outside research comfort zone to talk at the IETF about standardizing Fiat-Shamir and Σ-protocols. You can check out my slides here
datatracker.ietf.org/meeting/122/...
March 16, 2025 at 6:32 PM
tumbolia.bsky.social
Went to a meeting where they told me the Force cannot be double-spent and it made a lot of sense
March 13, 2025 at 9:58 AM
tumbolia.bsky.social
knowledge and feelings
March 7, 2025 at 3:47 AM
tumbolia.bsky.social
you're welcome, academics

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February 25, 2025 at 6:36 AM
tumbolia.bsky.social
I have updated my work on keyed-verification anonymous credentials, which is now 80 pages long and single authored. May it rest in peace 🪦

eprint.iacr.org/2024/1552.pdf
eprint.iacr.org
February 25, 2025 at 6:14 AM
tumbolia.bsky.social
It’s telling me something
February 24, 2025 at 5:12 PM
tumbolia.bsky.social
did a small blog post introducing anonymous credentials on OONI, a tool that measures censorship across the globe 💅
Probe Security Without Identification
An overview of the current literature on anonymous credentials and how we will be designing and implementing an anonymous credential system for use in OONI Probe.
ooni.org
February 21, 2025 at 5:35 PM
tumbolia.bsky.social
credential designers and identity-fluid users
February 18, 2025 at 3:37 AM
tumbolia.bsky.social
Thrilled to be emerging from my research cave for a trip around Asia
🇸🇬 Singapore (17-22 Feb) NUS
🇹🇼 Taipei (22 Feb - 8 Mar) RigthsCon, Community Privacy Residency
Are friends around?
a portrait of a men getting out of their tomb
February 15, 2025 at 10:00 AM