Lynn Engelberts
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lynnengelberts.bsky.social
Lynn Engelberts
@lynnengelberts.bsky.social
140 followers 53 following 5 posts
PhD candidate at Centrum Wiskunde & Informatica (CWI) and QuSoft | Designing quantum and classical algorithms for post-quantum cryptanalysis 🔍
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lynnengelberts.bsky.social
Excited to share our new paper on module-lattice reduction! 📄
We analyze the average-case behavior of module-BKZ, identifying when structure offers an advantage over standard BKZ and when the benefits are less clear. We also highlight several open directions for future work.
eprint.ing.bot ePrint Updates @eprint.ing.bot · 28d
Predicting Module-Lattice Reduction (Léo Ducas, Lynn Engelberts, Paola de Perthuis) ia.cr/2025/1904
Abstract. Is module-lattice reduction better than unstructured lattice reduction? This question was highlighted as ‘Q8’ in the Kyber NIST standardization submission (Avanzi et al., 2021), as potentially affecting the concrete security of Kyber and other module-lattice-based schemes. Foundational works on module-lattice reduction (Lee, Pellet-Mary, Stehlé, and Wallet, ASIACRYPT 2019; Mukherjee and Stephens-Davidowitz, CRYPTO 2020) confirmed the existence of such module variants of LLL and block-reduction algorithms, but focus only on provable worst-case asymptotic behavior. In this work, we present a concrete average-case analysis of module-lattice reduction. Specifically, we address the question of the expected slope after running module-BKZ, and pinpoint the discriminant Δ_(K) of the number field at hand as the main quantity driving this slope. We convert this back into a gain or loss on the blocksize β: module-BKZ in a number field K of degree d requires an SVP oracle of dimension β + log (|Δ_(K)|/d^(d))β/(dlog β) + o(β/log β) to reach the same slope as unstructured BKZ with blocksize β. This asymptotic summary hides further terms that we predict concretely using experimentally verified heuristics. Incidentally, we provide the first open-source implementation of module-BKZ for some cyclotomic fields. For power-of-two cyclotomic fields, we have |Δ_(K)| = d^(d), and conclude that module-BKZ requires a blocksize larger than its unstructured counterpart by d − 1 + o(1). On the contrary, for all other cyclotomic fields we have |Δ_(K)| < d^(d), so module-BKZ provides a sublinear Θ(β/log β) gain on the required blocksize, yielding a subexponential speedup of exp (Θ(β/log β)). Image showing part 2 of abstract.
October 19, 2025 at 8:57 PM
Reposted by Lynn Engelberts
dulwichquantum.bsky.social
"Peter Shor states the obvious that there are no existing examples of quantum algorithms available on any quantum hardware that currently show quantum supremacy..."
www.linkedin.com/posts/victor...
Peter Shor states the obvious that there are no existing examples of quantum algorithms available on any quantum hardware that currently show quantum supremacy and while factoring could potentially… ...
Peter Shor states the obvious that there are no existing examples of quantum algorithms available on any quantum hardware that currently show quantum supremacy and while factoring could potentially b...
www.linkedin.com
September 28, 2025 at 7:31 AM
Reposted by Lynn Engelberts
ccanonne.github.io
From Stacey Jeffery's excellent plenary talk at #TQC2025, on "Composing #Quantum Algorithms"
The summary slide of Stacey's talk, explaining the differences between algorithms composition in the classical randomized and the quantum worlds, with links to surveys and papers.
September 16, 2025 at 5:08 AM
lynnengelberts.bsky.social
High school reunion, 10 years later. Great to catch up with old classmates and friends!
My graduating class, 10 years after finishing high school, standing by a tree we once gifted to the school, now replanted.
July 7, 2025 at 8:29 PM
lynnengelberts.bsky.social
Had an incredible time in Bordeaux last week at a workshop on algebraic lattices in cryptography! 💎

Huge thanks to Alice Pellet-Mary for organizing and giving me the opportunity to present our recent SIS^∞ paper (eprint.iacr.org/2025/575), to appear in CRYPTO 2025!
Me presenting our recent work to the other workshop participants in Bordeaux
June 24, 2025 at 8:35 AM
Reposted by Lynn Engelberts
sejaques.bsky.social
An out-of-schedule update to my quantum landscape chart: sam-jaques.appspot.com/quantum_land..., prompted by
@craiggidney.bsky.social 's new paper: arxiv.org/abs/2505.15917.

A startling jump (20x) in how easy quantum factoring can be!

Also: much improved web design!
A chart for quantum computers, of number of qubits versus error rate, on a logarithmic scale. Broadly it shows a large gap between current quantum computers in the bottom left, and a curve in the top right of the resources they need to break RSA.
June 19, 2025 at 6:52 PM
lynnengelberts.bsky.social
Thanks @qctip2025.bsky.social for this inspiring conference! Great talks, great people, great vibes.
jenseisert.bsky.social Jens Eisert @jenseisert.bsky.social · Apr 24
The group photo of #QCTiP2025, held at @freieuniversitaet.bsky.social and the Harnack House of the Max Planck Society. This is an impressive crowd of active researchers interested in quantum computing theory in practice.
April 25, 2025 at 3:00 PM
lynnengelberts.bsky.social
Excited to join Bluesky! I’m a PhD candidate at CWI and QuSoft, working on quantum & classical algorithms for post-quantum cryptanalysis 🔑. Check out our recent paper here: arxiv.org/abs/2503.23238. Looking forward to connecting with others in quantum computing, cryptography, and beyond!
April 1, 2025 at 7:22 PM