Ryan Rueger
ryan@rueg.re / picture / key / git

Interested in algorithmic arithmetic geometry and number theory for applications in post-quantum isogeny-based cryptography.

Pre-doctoral researcher at IBM Research Zurich, pursuing a PhD from the Technical University of Munich. Advised by Luca De Feo and Lorenz Panny.

Research

CORAL: Faster Isogeny Group Action For Post-Quantum NIKE
with Andrea Basso, Giacomo Borin and Sina Schaeffler
[pdf | compact] [code]
To appear at Crypto ‘26

On the Active Security of the PEARL-SCALLOP Group Action
with Tako Boris Fuotsa, Marc Houben, Gioella Lorenzon and Parsa Tasbihgou
[pdf | compact | ePrint | Springer] [cite]
Published at PQCrypto ‘26

PEGASIS: Practical Effective Class-Group Action using 4-Dimensional Isogenies
with Pierrick Dartois, Jonathan Komada Eriksen, Tako Boris Fouotsa, Arthur Herlédan Le Merdy, Riccardo Invernizzi, Damien Robert, Frederik Vercauteren and Benjamin Wesolowski
[pdf | compact | ePrint | Springer] [code | mirror] [cite | C:DEFMIR25]
Published at Crypto ‘25

Talks

MaGIC'26 - Workshop on Group Actions in Cryptography
CORAL: Faster Isogeny Group Action For Post-Quantum NIKE
[slides] Borgo Lanciano, Italy

Isogeny Club
CORAL: Faster Isogeny Group Action For Post-Quantum NIKE

TUM Isogeny Seminar
Restricted Computation of the Isogeny Class-Group Action in Dimension 2
Munich, Germany.

Swissogeny Day #4
On the Active Security of the PEARL-SCALLOP group action
[slides] Lausanne, Switzerland.

Isogeny Days #6
On the concrete classical hardness of the supersingular isogeny problem
[slides] Leuven, Belgium. Invited talk

SIAM Conference on Applied Algebraic Geometry
PEGASIS: Practical Effective Class Group Action using 4-Dimensional Isogenies
[slides] Madison, USA.

Workshop on the mathematics of post-quantum cryptography
On Cryptographic Group Actions from Isogenies
[slides] Zurich, Switzerland.

Swissogeny Day #2
PEGASIS: Practical Effective Class Group Action using 4-Dimensional Isogenies
[slides] Zurich, Switzerland. Invited talk

Activities

Isogeny Seminar, Munich
Talk [slides]

Asiacrypt ‘25, Melbourne
Subreviewed

Swiss Crypto Day, Lausanne
Attended

Swissogeny Day #3, Zurich
Attended

AcrticCrypt ‘25, Longyearbyen
Subreviewed

Eurocrypt ‘25, Madrid
Subreviewed & Attended

SQI Party, Lleida
Attended

SNSF Scientific Image Competition
Won jury distinction award

Swiss Crypto Day, Lugano
Short talk [slides]

Isogeny Reading Group, Remote
Presented topic on torsors

Swissogeny Day #1, Lausanne
Attended

Isogeny Seminar, Munich
Talk [slides]

Isogeny days #5, Leuven
Attended

Eurocrypt ‘24, Zurich
Attended

Theses

Computing the isogeny class-group action on ordinary elliptic curves by going into higher dimensions
[pdf | ETH RC] [code] [slides]
Master thesis

Taylor Expansions of Modular Forms at CM Points
[pdf | ETH RC] [code]
Semester thesis

Eta Products
[pdf | ETH RC] [code]
Semester thesis

Blog

Installing and benchmarking Scott's ad-hoc finite field arithmetic

Is it "GPG" or "PGP"?

Regenerating `initramfs` from another snapshot with `mkinitcpio`

Cycling Zurich to Locarno via San Bernadino

Natively pretty printing `ls` output

Passwordless Git over HTTP(s) for Overleaf

Using NASA DEM data to create high resolution contour lines with QGIS

Groups of Order 4 are Commutative