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Julian Loss

@julianloss.bsky.social

I’m a cryptographer working on digital signatures, consensus algorithms, and more. Professor for Computer Science at Ruhr University Bochum.

38 Posts331 Follower140 Folgt
Julian Loss@julianloss.bsky.social · last yr.

New paper at Crypto 2025! We revisit one of the famous works of King et al. on leader election/consensus and show that the original paper’s proof has several major gaps. Although we aren’t able to prove the original protocol secure, we suggest a suitable modification along with a full proof.

ePrint Updates@eprint.ing.bot · last yr.

Leader Election with Poly-logarithmic Communication Per Party (Amey Bhangale, Chen-Da Liu-Zhang, Julian Loss, Kartik Nayak, Sravya Yandamuri) ia.cr/2025/1016

Abstract. The leader election problem requires a set of n parties, out of which up to t can be Byzantine, to elect a leader uniformly at random such that no two parties disagree on the elected leader and an honest leader is elected with constant probability. The Scalable Leader Election protocol published in SODA’2006 is an important breakthrough in solving this problem efficiently for all but o(1) of the parties. They achieve a protocol for $t < (\frac{1}{3} - \epsilon)n$ (for ϵ = o(1)) in the full-information setting such that every party only sends polylog n bits. In this paper, we revisit their work and show that there are subtleties in the protocol that are not dealt with in the analysis. In particular, two mechanisms related to “silencing” parties and dealing with “bad nodes” are at odds with each other, which is why the existing analysis is insufficient. We present these concerns in detail and subsequently present a modification to their protocol with a corresponding analysis to solve leader election with the desired metrics.
Julian Loss@julianloss.bsky.social · last yr.

What’s up, long time no see. I decided to move here after Twitter/X became unusable, but I realized that this was actually a great opportunity to get off of social media for good, read a book, go outside, and make some new friends. Anyway, I’m back; what did I miss?

Julian Loss@julianloss.bsky.social · 2y ago

I live in Germany which is typically reluctant to adopt digital/electronic solutions to common tasks, payments in particular. However, QR-code bills have become widely popular here and I think that’s a really great development as they are so convenient. How widely are these used in other countries?

Helger Lipmaa@helger.bsky.social · 2y ago

Finally, a formal hello. Cryptographer. I worked on ZK (zero-knowledge) before it was cool --- I still have those voices in my head from 1998 telling me that I should do something that actually matters. One of my blunders was to recommend Estonia to use ZK in e-voting... back in 2001.

Julian Loss@julianloss.bsky.social · 2y ago

New paper at SODA 25: eprint.iacr.org/2024/770 We show that you can broadcast in sublinear rounds with dishonest majority given only a bare PKI setup and a uniform CRS. Prior work in this setting assumes a trusted dealer/correlated setup.

Sublinear-Round Broadcast without Trusted Setup

Byzantine broadcast is one of the fundamental problems in distributed computing. Many of its practical applications, from multiparty computation to consensus mechanisms for blockchains, require incre...

eprint.iacr.org

Elisa Granato@prokaryota.bsky.social · 2y ago

'Tis the season ... of UK research fellowship interviews! Here are some tips & tricks to help you prepare - featuring a list of 100(!) common Q&A questions elisagranato.com/how-to-apply...

How to apply for a (UK) postdoc fellowship - Elisa Granato

How to apply for a (UK) postdoc fellowship Disclaimer: this guide was written based on my experience applying for (and being awarded) a BBSRC Discovery Fellowship in 2020/2021. Some of this might appl...

elisagranato.com

Julian Loss@julianloss.bsky.social · 2y ago

I’m new here, so I’ll briefly introduce myself. My name is Julian and I’m a cryptographer who also frequently dabbles in distributed algorithms. In my free time, I train for road races (mostly half marathons) and do nerdy things. My wife and I have three adorable cats called Kami, Sweep and Janus.