Overview
Guillaume D is a co-founder of BeHack and is based in Brussels. He took up that role in May 2022. Since September 2025 he has been an ambassador for Cresco Cybersecurity, having co-founded the company in June 2020 and led its hackers until September 2025. He has also owned Deterville consulting since August 2019.
Before that he co-founded Redcactus in May 2019, where he was cybersecurity leader until June 2020. He co-founded the Cyber Security Agency in January 2017 and served as its operations officer until May 2019, and in April 2017 he co-founded Machinerycash, working as its cyber strategist until December 2018.
He studied economics at the institut de l'Assomption from 2011 to 2016, obtaining a CESS.
Career history
In the news
- After 32 years of active production with the IBA cyclotron, Cyclone® 18/9, Herz- und Diabeteszentrum NRW, Bad Oeynhausen is preparing for its next chapter with the installation of a new cyclotron, Cyclone® KIUBE, to continue this remarkable success story. Discover this project during the poster session presented by Antje Uhlending and the HDZ-NRW team at WTTC20 in Nara, Japan. Looking to optimize your radiopharmaceutical production needs? Connect with our IBA experts, Benoit Nactergal and Guillaume D., at WTTC from August 23 to 27.
- The average Belgian company is attacked hundreds of times a week. Most of those attempts are blocked, automated, shrugged off. But the number climbs every year, and it only takes one of those hundreds getting through on the wrong afternoon. Here's what that number actually means. Security isn't an event you prepare for once. It's a siege that never lifts. The attacker can fail nine hundred times and still win on attempt nine hundred and one. You have to be right every single time. They have to be right once. Defence is the only
- A few weeks ago, a Belgian hospital had to postpone surgeries and transfer patients to other sites. Not because of a storm. Not because of a strike. Because of a cyberattack. Servers down. Systems locked. Seven patients moved while the hospital fought to get its own network back. We talk about cybersecurity in terms of data and money. Here's the part that doesn't fit on a slide. When a hospital goes down, the damage isn't measured in euros. It's measured in delayed operations and patients sent elsewhere. Then it got worse. The same
- Give me your full name and where you work. In about twenty minutes, I'll tell you your home address, the model of your car, where you went on holiday last summer, the name of your dog, and roughly what you paid for your house. You never posted most of that. You didn't have to. Other people did. A tagged photo. A public land registry. A leaked database from a service you forgot you signed up for in 2017. A running app that shares a little more than you think. This is called OSINT, open source intelligence, and it's the quiet first
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