I am Mathias Hall-Andersen (“rot256” on the internet), currently a final year PhD student in theoretical cryptology at Aarhus University with Jesper Buus Nielsen as my advisor. I have a broad interest in both theoretical and practical information security, as well as privacy enhancing technologies including: cryptography, cryptanalysis, coding theory, reverse engineering, vulnerability research and anything which lies in the intersection. I love building and breaking real-world systems; particularly when they involve cryptography.

In my free time I play/organize CTFs with Kalmarunionen / Norsecode, I also work on open source software and enjoy various types of swing dancing. On this site I post cryptography related technical content, ideas too small for a paper, projects I have been working on and write-ups for CTF challenges (usually exploitation / reversing / cryptography challenges).

Education

PeriodTitleInstitution
2020 - 2024PhD Candidate in Theoretical CryptographyAarhus University (CS Dept.)
2022 (fall)Visiting ResearcherBoston University (BUSec)
2017 - 2020Master in Computer ScienceUniversity of Copenhagen
2019 (fall)Master Thesis (Contingent Payments)Aarhus University
2018 (fall)ExchangeETH Zürich (D-INFK)
2017Bachelor Thesis (Linear Cryptanalysis)Technical University of Denmark
2014 - 2017Bachelor in Computer ScienceUniversity of Copenhagen

Work

PeriodTitleInstitution
2020 - 2024PhD StudentAarhus University
2023 (summer)Internship, Research / Engineering, FromagerGalois
2022 (summer)Internship, Cryptographic Engineering (Rust)O(1) Labs
2021 (summer)Internship (Development/Research on DARPA SIEVE)Trail of Bits
2020 (fall)Instructor in Distributed Systems and SecurityAarhus University
2020 (summer)Internship (Development/Research on DARPA SIEVE)Trail of Bits
2020 (spring)External lecturer in Proactive Computer SecurityUniversity of Copenhagen
2019 (fall)Open source development on WireGuard-rs
(NGI; Next-Generation Internet grant)
NLnet (Sponsor)
2019 (spring)Instructor in Proactive Computer SecurityUniversity of Copenhagen
2018 (summer)Internship (Security Consultant – Cryptography)NCC Group, New York
(Cryptography Services)
2017 (fall) - 2018Teaching Assistant in Practical CryptologyTechnical University of Denmark
2017 (summer)Google Summer of Code (created WireGuard-go)WireGuard (Linux Foundation)
2016 (fall)Instructor in Computer SystemsUniversity of Copenhagen
2016Student AssistantDeloitte Cyber Risk Services
2015Java ProgrammerSkandinaviska Enskilda Banken

Research

Preprints

Publications

Languages

Fluent in Danish, English, Rust, Python, Sage, C, Go, LaTex, a slew of assembly languages and cryptographic jargon. Shaky in a lot more…

Writing

A few examples of my technical writing:

Contact

Githubhttps://github.com/rot256
Personal Email\(\text{math}\)\(\text{ias}\)\(@\)\(\text{hall-an}\text{dersen.dk}\)
PGP Key/key.asc or keybase.io, Fingerprint: 71e1ec2b778745710667d51dae331b20b3c8a5c2
Websiterot256.dev – you are looking at it.
DBLPhttps://dblp.org/pid/225/9829.html

Questions? Comments? Interesting projects? Need help building/breaking cryptography?

Feel free to drop me an email :)