Peter Scholl
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schollster.bsky.social
Peter Scholl
@schollster.bsky.social
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Reposted by Peter Scholl
proofnerd.bsky.social
New paper with Vitor Pereira and Peter Scholl (@schollster.bsky.social)!

We found flaws in a supposedly formally verified security proof of LPZK, leading to attacks on soundness and zk.
The culprit: a mismatch between definitions in their code and the original LPZK papers.

cic.iacr.org/p/2/3/24
Screenshot from CiC website: Who Verifies the Verifiers? Lessons Learned from Formally Verified Line-Point Zero-Knowledge Authors Sabine Oechsner, Vitor Pereira, Peter Scholl
October 7, 2025 at 7:21 AM
schollster.bsky.social
Excited to do more research on the real-world security of MPC with @proofnerd.bsky.social, thanks to this grant. We plan to hire some interns for this next summer.

Congrats to all the other recipients so far, and to Zama for a smooth application process, ~1 month from announcement to notification!
smartcryptology.bsky.social Nigel Smart @smartcryptology.bsky.social · Jun 3
4) Nadia Heninger @nadiaheninger.bsky.social and Miro Haller @mirohaller.bsky.social‬ (UC San Diego),

5) Sabine Oechsner @proofnerd.bsky.social‬ (VU Amsterdam) and Peter Scholl @schollster.bsky.social‬ (Aarhus University),

6) Victor Lomné (Ninja Lab)
June 4, 2025 at 10:15 PM
schollster.bsky.social
Happy our paper on the real-world security of MPC implementations is finally out! This project goes back to Frederik & Alexander's masters thesis from 2 years ago @csaudk.bsky.social, it's not easy work but hope to see more of this type of research in future.
proofnerd.bsky.social Sabine Oechsner 🟥 @proofnerd.bsky.social · May 5
Our paper on attacking concurrent MPC implementations is finally on eprint 🎉
(And @schollster.bsky.social will present it at S&P 2025!)

A summary 🧵
eprint.ing.bot ePrint Updates @eprint.ing.bot · May 5
Rushing at SPDZ: On the Practical Security of Malicious MPC Implementations (Alexander Kyster, Frederik Huss Nielsen, Sabine Oechsner, Peter Scholl) ia.cr/2025/789
May 5, 2025 at 8:12 AM
Reposted by Peter Scholl
mkskeller.bsky.social
Shout-out to my colleagues for the responsible disclosure of security issues in MP-SPDZ. They have been fixed in 2023.
eprint.ing.bot ePrint Updates @eprint.ing.bot · May 5
Rushing at SPDZ: On the Practical Security of Malicious MPC Implementations (Alexander Kyster, Frederik Huss Nielsen, Sabine Oechsner, Peter Scholl) ia.cr/2025/789
Abstract. Secure multi-party computation (MPC) enables parties to compute a function over private inputs while maintaining confidentiality. Although MPC has advanced significantly and attracts a growing industry interest, open-source implementations are still at an early stage, with no production-ready code and a poor understanding of their actual security guarantees. In this work, we study the real-world security of modern MPC implementations, focusing on the SPDZ protocol (Damgård et al., CRYPTO 2012, ESORICS 2013), which provides security against malicious adversaries when all-but-one of the participants may be corrupted. We identify a novel type of MAC key leakage in the MAC check protocol of SPDZ, which can be exploited in concurrent, multi-threaded settings, compromising output integrity and, in some cases, input privacy. In our analysis of three SPDZ implementations (MP-SPDZ, SCALE-MAMBA, and FRESCO), two are vulnerable to this attack, while we also uncover further issues and vulnerabilities with all implementations. We propose mitigation strategies and some recommendations for researchers, developers and users, which we hope can bring more awareness to these issues and avoid them reoccurring in future. Image showing part 2 of abstract.
May 5, 2025 at 5:15 AM