365 Sustainable Decisions Challenge

 📚 "Does your books really make a difference?" Yes, they do: 🌍 Yesterday, on the final day of my course for climate activists and others working hard for a healthier planet, a participant bought my book and asked how widely it is read. 😁 To be honest, I didn't know the latest numbers, so I looked them and I was pleasantly surprised myself! 📖 A Guide to a Healthier Planet has now been downloaded: • Volume 1: more than 46,500 times • Volume 2: more than 22,000 times • Volume 3: more than 7,700 times (Combined figures for the English editions and German translations.) 🌱 The goal of these books is simple: to make the science behind climate change, pollution, and biodiversity accessible to everyone, while offering practical ideas for what each of us can do in our daily lives to help. 💪 When we talk about creating a healthier planet, it's easy to feel that individual actions don't matter. But if every reader takes just one action inspired by these books, the ...

 🎉 I'm happy to share that I earned another certification this week! 💻️ This one was special. Back in late 2014, I made the switch from Windows to Linux to prepare for a new role in cybersecurity. More than a decade later, I can confidently say it's one of the best technology decisions I've ever made. 📖 Although I was already very comfortable working with Linux, studying for this certification pushed me to deepen my knowledge even further. I rehearsed concepts I use every day, but also studied new topics, and even learned a few things that will make my day-to-day work easier and more efficient. 🚀 Learning never stops in cybersecurity, which is awesome! And although I'm happy that it is done now, I'm already working on the next challenge! #Linux #CyberSecurity #ContinuousLearning #ProfessionalDevelopment #Certification

  🎤 Last month, I had the pleasure of being a keynote speaker at the wonderful CANCOM Security Day 2026 in Vienna. When you watch the event summary, do you notice something? 💻 After arriving and receiving a warm welcome, I made sure everything was ready for my keynote. Once that was taken care of, I had time to walk around the venue and enjoy some inspiring conversations with attendees. 👬 As I looked around, I noticed something familiar: there were almost only men. To be honest, this was not surprising. When I started my career in #cybersecurity, most of my colleagues were men. Today, when I teach, most of my students are men. And at the majority of cybersecurity conferences and industry events I attend, most participants and speakers are men. Cancom Security Day was not the exception: it reflected the reality of our industry. 👭 Of course, I would love to see more women enter and thrive in cybersecurity. The field needs diverse perspectives, experiences, and voices. 🫅 At ...

💡 The more I learn about AI security, the more I know about that using AI without proper security mechanisms is a serious risk. 🆘 For example, during a recent security test, I asked an AI chatbot to do something very simple: repeat the word "help!" indefinitely. And that's exactly what it did. help! help! help! help! ... And on and on it went, until I manually stopped it. 💸 While this might seem harmless, every generated token consumes compute resources and generates cost. At scale, these kinds of prompts can become very expensive. 👛 This type of attack is known as Denial of Wallet (DoW). Unlike a traditional Denial of Service (DoS) attack, where the goal is to make a service unavailable, a Denial of Wallet attack aims to drain your budget by forcing excessive consumption of AI resources, tokens, API calls, or compute power. 💸 The threat is very real. Recent research demonstrated attacks that increased AI agent execution costs by up to 658 times while still p...

🤩 I went to a festival for a casual stroll and somehow ended up being interviewed on the radio! This is how that happened: ☀️ Last weekend, I visited a festival in my city with no plans other than to wander around and enjoy the great weather. As I was enjoying myself, I had wonderful conversations with people I had never met before, and some of them turned out to be surprisingly fruitful. 🎤 For example, I asked the local radio station what the word "frei" ("free") in their name actually means. This simple question led to a conversation about other topics and eventually in an invitation to talk on air about the litter-picking initiative I'm currently leading. 💚 It was a lot of fun. And it reminded me how valuable the skills we build in one area of life can be in another: the professional speaking experience I've developed through my work helped me communicate a cause I care deeply about without any preparation. 🔗 If you're looking for a speaker f...