# Simon-Philipp Merz

## About me

I am currently a PhD student in the Information Security Group at Royal Holloway, University of London. My supervisors are Simon R. Blackburn and Christophe Petit.

My doctoral research revolves around post-quantum cryptography and cryptanalysis with a special focus on isogeny-based cryptography. More generally, I am interested in computational number theory and various applications of pure mathematics to cryptography.

Before joining Royal Holloway, I obtained a BSc in Mathematics from the Free University of Berlin, an MSc in Pure Mathematics from Imperial College London and an MSc in Mathematics and Foundations of Computer Science from the University of Oxford.

## Publications

- On the Isogeny Problem with Torsion Point Information,
- Cryptanalysis of an oblivious PRF from supersingular isogenies,
- One-way functions and malleability oracles:

Hidden shift attacks on isogeny-based protocols, - On Index Calculus Algorithms for Subfield Curves,
- On Adaptive Attacks against Jao-Urbanik's Isogeny-Based Protocol,
- Another look at some isogeny hardness assumptions,
- Factoring Products of Braids via Garside Normal Form,

T. B. Fouotsa, P. Kutas, S.-P. Merz, Y. B. Ti

PKC 2022, ePrint 2021/153.

PKC 2022, ePrint 2021/153.

A. Basso, P. Kutas, S.-P. Merz, C. Petit, A. Sanso,

ASIACRYPT 2021, ePrint 2021/706.

ASIACRYPT 2021, ePrint 2021/706.

P. Kutas, S.-P. Merz, C. Petit, C. Weitkämper,

EUROCRYPT 2021, ePrint 2021/282.

EUROCRYPT 2021, ePrint 2021/282.

S.D. Galbraith, R. Granger, S.-P. Merz, C. Petit,

SAC 2020, ePrint 2020/1315.

SAC 2020, ePrint 2020/1315.

A. Basso, P. Kutas, S.-P. Merz, C. Petit, C. Weitkämper,

AFRICACRYPT 2020, ePrint 2020/244.

AFRICACRYPT 2020, ePrint 2020/244.

S.-P. Merz, R. Minko, C. Petit,

CT-RSA 2020, ePrint 2019/950.

CT-RSA 2020, ePrint 2019/950.

S.-P. Merz, C. Petit,

PKC 2019, ePrint 2018/1142.

PKC 2019, ePrint 2018/1142.

## Talks

- CWI Student Seminar, CWI Amsterdam, Amsterdam (virtual), 25 March 2022.
- Post-Quantum Cryptography Workshop, Birmingham (GBR), 22 March 2022.
- Isogeny-based Cryptography Workshop, Birmingham (GBR), 16 March 2022.
- ISG Research Seminar, Royal Holloway, Egham (virtual), 10 March 2022.
- ASIACRYPT 2021, Singapore (virtual), 7 December 2021.
- EUROCRYPT 2021, Zagreb (HRV), 18 October 2021.
- SAC 2020, Halifax, Nova Scotia (virtual), 23 October 2020.
- CT-RSA 2020, San Francisco (USA), 27 February 2020.
- ISF World Congress 2019, Dublin (IRL), 26 October 2019.
- PKC 2019, Beijing (CHN), 16 April 2019.

*Cryptanalysis of an Oblivious PRF from Supersingular Isogenies*, slides.

*SIDH and its Applications*, slides.

*SIDH and its Applications*, slides.

*Cryptanalysis of an Oblivious PRF from Supersingular Isogenies*, slides.

*Cryptanalysis of an Oblivious PRF from Supersingular Isogenies*, slides.

*One-way functions and malleability oracles:*

Hidden shift attacks on isogeny-based protocols, slides.

Hidden shift attacks on isogeny-based protocols

*On Index Calculus Algorithms for Subfield Curves*, slides.

*Another look at some isogeny hardness assumptions*, slides.

Invited talk on mathematical problems underlying elliptic curve and isogeny-based cryptography.

*Factoring Products of Braids via Garside Normal Form*, slides.

## Teaching and Refereeing

During the winter semester 2015-2016, I was a teaching assistant for the course*Computational Mathematics and Scientific Computing*.

For the following conferences I was a (sub)reviewer:

CRYPTO 2019, SAC 2019, MathCrypt 2019, AFRICACRYPT 2019, IMACC 2019, PKC 2020, ANTS 2020, AFRICACRYPT 2020, PKC 2021, PQCrypto 2021, ASIACRYPT 2021, SAC 2021, IMACC 2021, ANCS 2022, AFRICACRYPT 2022, ANTS 2022

I have been a reviewer for the following journals:

Advances in Mathematics of Communications;

IET Information Security;

Designs, Codes and Cryptography;