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Chelsea Komlo

@chelseakomlo.bsky.social

I’m at SBC and Simon’s for the next week, looking forward to seeing everyone!

Will be giving a talk on Thursday at Simon’s on our recent impossibility results on the adaptive security of threshold signatures- simons.berkeley.edu/talks/chelse...

On the Adaptive Security of Key-Unique Threshold Signatures

Abstract not available.

simons.berkeley.edu

August 3, 2025 at 1:08 PM

Chelsea Komlo

@chelseakomlo.bsky.social

2025: started out with Covid, got better, then relapsed into Covid 🤦‍♀️

January 15, 2025 at 12:39 AM

Chelsea Komlo

@chelseakomlo.bsky.social

Back to blue sky and happy new year!!!

January 4, 2025 at 4:31 PM

Chelsea Komlo

@chelseakomlo.bsky.social

After 3 years & 12 drafts, the RFC for FROST is complete! We hope this makes implementing FROST easier with fewer bugs 🐛

Thank you to everyone who helped by reviewing FROST security, submitting comments, and implementing the draft, this was a team effort 🙌💪

www.rfc-editor.org/rfc/rfc9591....

RFC 9591: The Flexible Round-Optimized Schnorr Threshold (FROST) Protocol for Two‑Round Schnorr Signatures

This document specifies the Flexible Round-Optimized Schnorr Threshold (FROST) signing protocol. FROST signatures can be issued after a threshold number of entities cooperate to compute a signature, ...

www.rfc-editor.org

July 6, 2024 at 2:05 PM

Reposted by Chelsea Komlo

John Schanck

@susurrusus.bsky.social

There's a mergesort step on page 12 that is costed at N log N. So I don't think this improves on Sam Jaques' eprint 2024/080 from a theoretical perspective. Nice implementation work though!

ePrint Updates @eprint.ing.bot · May 16

BGJ15 Revisited: Sieving with Streamed Memory Access (Ziyu Zhao, Jintai Ding, Bo-Yin Yang) ia.cr/2024/739

Abstract. The focus of this paper is to tackle the issue of memory access within sieving algorithms for lattice problems. We have conducted an in-depth analysis of an optimized BGJ sieve (Becker-Gama-Joux 2015), and our findings suggest that its inherent structure is significantly more memory-efficient compared to the asymptotically fastest BDGL sieve (Becker-Ducas-Gama-Laarhoven 2016). Specifically, it necessitates merely 2^(0.2075n + o(n)) streamed (non-random) main memory accesses for the execution of an n-dimensional sieving. We also provide evidence that the time complexity of this refined BGJ sieve could potentially be 2^(0.292n + o(n)), or at least something remarkably close to it. Actually, it outperforms the BDGL sieve in all dimensions that are practically achievable. We hope that this study will contribute to the resolution of the ongoing debate regarding the measurement of RAM access overhead in large-scale, sieving-based lattice attacks.

The concept above is also supported by our implementation. Actually, we provide a highly efficient, both in terms of time and memory, CPU-based implementation of the refined BGJ sieve within an optimized sieving framework. This implementation results in approximately 40% savings in RAM usage and is at least 2^(4.5) times more efficient in terms of gate count compared to the previous 4-GPU implementation (Ducas-Stevens-Woerden 2021). Notably, we have successfully solved the 183-dimensional SVP Darmstadt Challenge in 30 days using a 112-core server and approximately 0.87TB of RAM. The majority of previous sieving-based SVP computations relied on the HK3-sieve (Herold-Kirshanova 2017), hence this implementation could offer further insights into the behavior of these asymptotically faster sieving algorithms when applied to large-scale problems. Moreover, our refined cost estimation of SVP based on this implementation suggests that some of the NIST PQC candidates, such as Falcon-512, are unlikely to achieve NIST’s security requirements.

May 20, 2024 at 4:25 PM

Reposted by Chelsea Komlo

Alan Allport

@alanallport.bsky.social

Consider donating your eclipse glasses to Eclipse Glasses USA so schoolchildren in South America can use them in October. eclipse23.com/pages/donate...

Donate Used Eclipse Glasses | Eclipse Glasses USA

Not sure what to do with your used eclipse glasses now that the October 2023 eclipse has passed? Donate them to Eclipse Glasses USA. We will send them to school children in other countries for those c...

eclipse23.com

April 8, 2024 at 8:49 PM

Chelsea Komlo

@chelseakomlo.bsky.social

First podcast, check it out! :) zeroknowledge.fm/318-2/

Episode 318: Threshold Signature Schemes & FROST with Chelsea Komlo - ZK Podcast

In this week’s episode, Anna and Nico chat with Chelsea Komlo, Chief Scientist for the Zcash Foundation and member of the Cryptography, Security, and Privacy lab at the University of Waterloo. They d...

zeroknowledge.fm

April 5, 2024 at 1:13 AM

Chelsea Komlo

@chelseakomlo.bsky.social

This is jaw-dropping, wild news and should be criminal

techcrunch.com/2024/03/26/f...

Facebook snooped on users' Snapchat traffic in secret project, documents reveal | TechCrunch

A secret program called

techcrunch.com

April 1, 2024 at 12:19 AM

Reposted by Chelsea Komlo

François Dupressoir

@francois.dupressoir.eu

It's not a choice of one or the other.

Use the appendix, as an author, to make reviewers see the value of sticky reviews and make them more likely to ask chairs to turn them on!

March 31, 2024 at 12:55 PM

Chelsea Komlo

@chelseakomlo.bsky.social

If you are on a PC for an IACR conference, consider reaching out to the PC chairs to request “sticky reviews”, to allow reviews from prior submissions to IACR conferences to be visible! Let’s make science better! 💪

Nigel Smart @smartcryptology.bsky.social · Mar 30

This is actually possible with IACR venues and has been the case for over 10 years. They are called "sticky reviews".

Trouble is most PC chairs do not promote them, or have forgotten

March 30, 2024 at 8:25 PM

Chelsea Komlo

@chelseakomlo.bsky.social

I wish conferences asked papers to submit feedback received from prior submission attempts and a discussion of how the authors improved the paper since then… so much context is lost between submission attempts across different venues

March 30, 2024 at 5:04 PM

Chelsea Komlo

@chelseakomlo.bsky.social

Thanks for the amazing time #RealWorldCrypto, fantastic talks and conversations as always! See you next year in Europe :)

March 29, 2024 at 3:55 PM

Chelsea Komlo

@chelseakomlo.bsky.social

Changing my job title to “fancy cryptographer” thanks #RealWorldCrypto

March 25, 2024 at 3:11 PM

Reposted by Chelsea Komlo

ePrint Updates

@eprint.ing.bot

Arctic: Lightweight and Stateless Threshold Schnorr Signatures (Chelsea Komlo, Ian Goldberg) ia.cr/2024/466

Abstract. Threshold Schnorr signatures are seeing increased adoption in practice, and offer practical defenses against single points of failure. However, one challenge with existing randomized threshold Schnorr signature schemes is that signers must carefully maintain secret state across signing rounds, while also ensuring that state is deleted after a signing session is completed. Failure to do so will result in a fatal key-recovery attack by re-use of nonces.

While deterministic threshold Schnorr signatures that mitigate this issue exist in the literature, all prior schemes incur high complexity and performance overhead in comparison to their randomized equivalents. In this work, we seek the best of both worlds; a deterministic and stateless threshold Schnorr signature scheme that is also simple and efficient.

Towards this goal, we present Arctic, a lightweight two-round threshold Schnorr signature that is deterministic, and therefore does not require participants to maintain state between signing rounds. As a building block, we formalize the notion of a Verifiable Pseudorandom Secret Sharing (VPSS) scheme, and define Shine, an efficient VPSS construction. Shine is secure when the total number of participants is at least 2t − 1 and the adversary is assumed to corrupt at most t − 1; i.e., in the honest majority model.

We prove that Arctic is secure under the discrete logarithm assumption in the random oracle model, similarly assuming at minimum 2t − 1 number of signers and a corruption threshold of at most t − 1. For moderately sized groups (i.e., when n ≤ 20), Arctic is more than an order of magnitude more efficient than prior deterministic threshold Schnorr signatures in the literature. For small groups where n ≤ 10, Arctic is three orders of magnitude more efficient.

March 22, 2024 at 9:42 PM

Chelsea Komlo

@chelseakomlo.bsky.social

Hi Toronto! Looking forward to seeing everyone at #RealWorldCrypto 🇨🇦

March 21, 2024 at 12:30 AM

Chelsea Komlo

@chelseakomlo.bsky.social

I was asked today what the upper bound is on number of signers in threshold signature schemes used in practice today and I didn’t have a good answer…

I’m assuming consensus schemes are larger, but does anyone know of signing groups of > 20? That seems on the larger side

January 24, 2024 at 10:36 PM

Chelsea Komlo

@chelseakomlo.bsky.social

Apparently those leading the anti-diversity programs at US public universities believe “a healthy society requires patriarchy”- why in 2023 are women with voices and brains considered to be such a threat www.nytimes.com/interactive/...

January 22, 2024 at 11:03 AM

Chelsea Komlo

@chelseakomlo.bsky.social

I wish there was more of a culture in cryptography of reaching out to authors to carefully double check claims before writing these claims in reviews or related work.

I’ve seen *big* mistakes made- eg, by a reviewer that said my summary of my own prior work was wrong 🙃

January 20, 2024 at 3:45 PM

Reposted by Chelsea Komlo

Ana Marie Cox

@anamariecox.bsky.social

I did this. Please do this; if you are a person who can get pregnant, have them on hand. I used AidAccess.org. I have a vision for care access where people can ask other people for abortion pills the way we call out for tampons in a public restroom. Though I suppose not in a *public* restroom.

January 2, 2024 at 5:14 PM

Reposted by Chelsea Komlo

Natanael, Tech janitor

@natanael.bsky.social

Misuse resistant cryptography, but more. I want to see takes on it from more fields, like what do data centers need from it?

December 30, 2023 at 4:48 PM

Chelsea Komlo

@chelseakomlo.bsky.social

To anyone working on real-world cryptography- what would you like to see more of in cryptography research for 2024?

Readable papers? Performance measurements? Accounting for specific failure cases? More PQ? Acceptance of non-standard assumptions? Solving certain problems?

December 30, 2023 at 3:14 PM