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Cryptax

This website is personal and does not represent my employer

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CTFs and AI

CTFs and Artificial Intelligence. Post Ph0wn 2026 Thoughts. Update May 19, 2026: Re-phrased first paragraph. In particular, replaced the title “Myth #1 CTF players hate AI [..]” with “CTF players hate AI [..]: True or False?” because I found my title was too biaised. It did not express fairly enough the reality. Added a paragraph on my (current) opinion. Added references to foreman, Kabir and Sthack CTF My opinion, in short The “problem” of AI in CTFs is very complex, with pros and cons…

Reviewing the AI-generated submissions with AI

Reviewing the AI-generated submissions with AI I am a reviewer for several conferences, and you won’t be surprised to hear we are getting an increasing number of AI-generated submissions with close to 0 technical value. I don’t know yet if those are (1) pure spam, or (2) naive authors who hope to get selected. Why should I spend human brains and time on something which was generated in seconds by AI?

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Write-ups

THCon 2026 - Forensics Challenges

Don’t forget to lock This is the first challenge of the Forensics category. 1 We seized a suspect's computer and managed to capture a RAM dump before it was powered off, along with an encrypted disk. Your objective is to decrypt the drive. We get a chall.tar.gz Solving the challenge The tar.gz contains 2 files: an ELF and a raw: 1 2 3 drwxr-xr-x aurel/aurel 0 2026-03-09 16:46 files/ -rw-r--r-- aurel/aurel 1072693248 2026-03-09 16:46 files/disk.

OSINT Industries Christmas 2025 CTF

OSINT Industries Christmas 2025 CTF Find the Masked Man Description In this first challenge, a photograph was taken on December 3rd, 2023 around 18:00 and we must identify the nearest metro station in Paris. We also get a hint that the scene is located near the intersection of a Rue and an Avenue. Solution I crop on the part of the image that shows shops. I can distinctively read “Julien”, and then perhaps “Brasserie” or “Creperie” or something like that, and a shop name ending “Aid” (maybe an English name).

XMas Root Me 2025

Xmas Root Me CTF 2025 X-Mas Assistant Day 1 Description of the challenge “Meet your X-Mas Assistant! It will help you throughout this entire month of CTF, providing a brand-new way to interact with CTFd through a “futuristic” Chatbot UI. This assistant talks directly to the CTFd API for you! Try it now! Can you exploit its MCP quirks and uncover the flag? This is not a web challenge.Meet your X-Mas Assistant!

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