Pierre-Jean Grenier

Geek, cybersecurity engineer, and H2G2 fan

Hi! I'm Pierre-Jean. I love video games and open source projects, and I'm a big fan of Douglas Adams' Hitchhiker's Guide to the Galaxy. In short: I'm a geek! :) But I also like biking and hiking, when I'm not behind my computer.

I studied cyber security at École polytechnique (France) and Télécom Paris.

I've been an administrator of the French Wikipedia from 2011 to 2018; unfortunately I now have less time to devote to this great project. I programed a bot that still runs 24/7 there to help the community with administrative and technical work. I was mostly involved in the counter-vandalism unit, but also wrote the article about Apple's System 6. Being a part of this community was a great experience.

Some projects


Open source

A test tool for the Happy Eyeballs algorithm, that allows developers to simulate delays on DNS answers and the SYN-ACK answer during the TCP handshake. They can consequently test their Happy Eyeballs implementation with real experiments, and profile a webbrowser. Also provides some statistics as a feedback. Test it yourself!


Open source

Team work at École polytechnique with Paul-Ambroise Duquenne, François de Fouchécour, Guillaume Gette, Olivier Piau and Antonin Riffard

Aims at replacing the usual authentification on Wi-Fi via WPA2 or other password methods by a geolocation-based low-cost method, widely accessible to the public (this project was developed on OpenWRT). The user therefore has Internet access only when he is in authorized rooms. This could be used, for instance, by a hotel to give Internet access to its clients (only people that can enter a booked room) or in a café where you want the consumers to have Internet access.

Work experience


NATO (2019)

6-month internship at the NCIRC (NATO Computer Incident Response Capability). Worked on Cuckoo, MISP (made some PR and wrote the cuckooimport module), helped the team with reverse engineering and malware analysis. Gained a better knowledge of threat actors.

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Cisco (2018)

4-month research internship at Cisco France. Worked on new methods to detect Advanced Persistent Threats (APTs) malware.

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Cisco (2017)

2-month internship at Cisco France. Developed HeyeHack, a test tool for the Happy Eyeballs algorithm. The tool is hosted by Cisco and opened to all developers who want to use it. It also provides statistics feedbacks.

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Officer Cadet

Gendarmerie Nationale (2015 - 2016)

6-month military internship at the National Gendarmerie (one of the two French police forces) as an Officer cadet. Assigned to the C3N, a Numeric Cyber-Criminality Squad, as a darkweb expert. Awarded the National Defence Medal for this work.

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Other experience


Binet Réseau (2017 - 2018)

President of the Binet Réseau, a student association of École polytechnique that aims at providing various Internet services. More than 1,200 daily users, handles half a dozen different servers.

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