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...

 🥳 I'm happy to see that our recent #litterpicking event was mentioned in the newspaper, as it has inspired others to join our initiative and help keep our city clean!

  🌱 Today showed again that one person can spark real change: 💭 People often think a single action by one individual won’t make much of a difference. Today proved the exact opposite. 📩 A few weeks ago, a neighbor reached out about her street and the nearby park being overwhelmed by litter. Instead of accepting it as “just the way things are,” she took action. Together, we decided to organize a community litter-picking event. 🤝 Today, that idea became reality. 👥 She invited her neighbors, and I invited our litter-picking community. In the end, around 15 adults and 15 children showed up, and even more children joined in after seeing what we were doing. ✨ What started with one email turned into something much bigger: a clean park, a cleaner street, happy faces, new friendships, and a powerful learning experience for the children. We also spent the afternoon outdoors, active, and doing something meaningful together. 🏡 This is what community looks like. This is what happens...

  😲 A normal morning - until suddenly everything comes to a standstill: systems locked, data encrypted, a ransom demand for $80,000. That’s what I talked about in a recent episode of the SWR podcast. 💰 I was a guest on SWR’s “Streifenfragen” and explained why ransomware is so attractive to attackers and what really lies behind such attacks. I also addressed the crucial question: Should you pay or not? 🌍 And the investigators explained: such cases are rarely local. They are part of international networks, highly professionally organized, and often difficult to track down. ❣️ My most important takeaway: Prevention isn’t a “nice-to-have”, it is essential for survival. Backups, security strategies, and awareness determine whether a company remains operational or, in the worst-case scenario, goes bankrupt. 🎧 An exciting episode (in German) about cybercrime, cross-continental investigative work, and the reality of digital extortion. https://www.swr3.de/podcasts/cybercrime-auf-de...

  🫨 Imagine coming home and realizing someone got in. Nothing is broken, but drawers are open, rooms have been checked, and things are missing. 🏠️ I often feel like the burglar who did this when I test websites. I log in as a normal user and start looking around. With a small change, I suddenly end up in places I shouldn’t be. Other people’s accounts. Admin pages. Private data like names, email addresses, and order details. 😇 But in my case, probably no one will ever notice if I wouldn’t explain this in the report. 💡 I see this more often than you’d expect. If you run a website and have ever wondered how easy it is for someone to “walk in”, feel free to reach out.

  ♣️ ♦️ Last weekend I visited the Board Game Archive in Haar. As a board game author, it was lovely to be surrounded by so many games! And yet, I learned something I did not expect. 🎲 The archive contains over 20,000 board games, from very old to very recent, from heavily played to completely new. Some of these new games are still wrapped in the plastic foil they were shipped in. It seems harmless, but it is not. 🫁 Over time, this plastic breaks down into microplastics, tiny particles that are almost impossible to remove. They can become so small that they linger in the air, and people working in or visiting the archive may breathe them in, potentially harming their health. 🙏 I am very grateful for the fantastic tour and the important work being done there. As a small contribution, I will be donating my game "Meine Freundin Conni: Kunterbunter Knobelspaß" to the archive. 💡 And now I know: I will make sure to remove the foil beforehand. Every little bit helps!

  I'm honored to be rated as Top 100 Trainer by Speakers Excellence Deutschland Holding GmbH! I offer trainings, keynotes, andpresentations on three hot topics: #cybersecurity, #artificialIntelligence, and #sustainability - whether individually or where these fields intersect. I also test whether your website can be hacked. 💡 Interested in bringing fresh insights to your team, event or website? Let’s connect and explore collaboration opportunities!

  💚 What an incredible day! Last Saturday’s river #cleanup I co-organized was a huge success: with over 70 amazing volunteers joining at different times and locations along the Neckar river. 💪 Together, we removed over 30 bags of waste and a lot signs/bikes/trolley from both the river and its banks, making a real, visible difference. ❤️ But beyond the cleanup itself, what truly stood out was the energy: people coming together, connecting, and genuinely enjoying the experience while caring for our environment. It was inspiring and honestly heartwarming to witness. 🌱 Organizing this alongside three dedicated fellow citizens made it even more special and seeing so many others step up and join reminds me that far more people care than we might think in our day-to-day lives. 🙏 Even after a full day of non-stop action, I'm full of energy. Feeling so incredibly grateful and motivated… I know many more events will follow. Stay tuned for the next one!

  🧹 Today, I organize a #litterpicking event together with a local school. What felt special was that moment I walked in, I was greeted by around 60 children, buzzing with excitement to get started. ❤️ In fact, I barely made it through my explanation before they were already on their feet, ready to take action. That was so heartwarming! 👧 And the great think was that the idea came from two girls who simply decided they wanted to make a difference. And while the playground at first glance looked clean, we in the end had collected five full bags of trash. 💪 To me, this is a powerful reminder that anyone - no matter what age - can turn ideas into action with teamwork. And we will repeat this event at some point in the future!

  🎤 Today, I had the pleasure of being interviewed by Dennis Brunnecker for a radio documentary on plastic pollution. 💚 We spoke about the litterpicking initiative I’m leading, as well as my work in communicating the science behind this growing environmental challenge. 🧹 It turned was a wonderful conversation with great questions. I’m really looking forward to continuing our conversation in a more hands-on way when he joins the river cleanup this Saturday. Conversations are important but action is where change truly begins. #cleanup #environment #sustainability

Today we were interviewed by the local newspaper about the river #cleanup we’re coordinating this Saturday. We expect a lot of people and I’m sure their report inspires even more to join. I’m excited and really looking forward to it!

 💚 Today, I collected 14 bags of trash from nature! These tangible results are one of the many reasons I love litterpicking so much. Now I feel very satisfied and am sure I will sleep very well! 😊

  💬 Many of us assume our WhatsApp messages are completely safe because they’re protected by end-to-end encryption. But this is not quite true! ⚛️ Last week, I had the chance to join a guided tour at the Fraunhofer Institute for Industrial Engineering IAO "Quantum Lab". While AI continues to dominate headlines, researchers are already working on the next potentially world-changing technology: Quantum computing. 💡 One of the mind-blowing characteristics of quantum computers is that they can solve certain mathematical problems much faster than today’s computers. This is important to know, because many of the #encryption methods we rely on today – including those used to secure WhatsApp messages – are based on mathematical problems that are extremely difficult for current computers to solve. ❗ Quantum computers could change that. ℹ️ This means that your messages are safe today, but once quantum computers mature, they may be able to break today’s encryption standards far ...

  🥹 Wow, I didn’t expect this and made it an unforgettable experience: 🎇 At the Winterconference organised by the German Speakers Association, I was genuinely blown away by the positive feedback I received after my keynote! 🤖 This year’s conference focused on #ArtificialIntelligence, exploring both its incredible opportunities and the challenges it brings. As a #cybersecurity expert, I chose to focus on a side of #AI that often surprises people: how AI systems can be hacked. 🎤 During my keynote, I demonstrated how a chatbot can be manipulated to reveal sensitive personal data and even answer unethical questions. I could literally see stunned faces and jaws dropping. 😁 I truly enjoyed giving this presentation. And judging by the reactions in the room, the audience enjoyed it just as much. 🙏 What made the feedback afterwards especially meaningful to me is who it came from: fellow professional speakers who are used to seeing excellent presentations. Receiving such positive...

  🎉 And the winner is… me! 😄 🎤 Last week at the Winterconvention, organized by the German Speakers Association, I participated in a unique prompting competition. The challenge? Get #AI to generate the funniest possible answers based on the exercises given. 🏆 I think my everyday experience with prompting, and my background as an ethical hacker, testing AI #chatbots gave me the edge… because I won! 😁 It was such a fun and inspiring experience, and I’m beyond grateful for the amazing prize: an invitation to an exclusive meeting with “Speaker of the Year” award winners. As a professional speaker myself, this is a truly unique opportunity! 🚀 Feeling motivated, inspired, and ready for the next AI penetration test for more chatbot hacking! #ethicalHacking #penetrationTesting

  A few days ago, I had a blind date. 😁 On my way to the German Speakers Association Winterconference, I met my colleague Jörg Sutter for the first time. We had never seen each other before, but agreed to meet at our reserved seats on the train. It turned into hours of great conversation. ☀️ Jörg shared how he helps people successfully install solar panels and navigate the practical realities behind the technology. Even though I wrote about solar energy in my latest book (A Guide to a Healthier Planet 3), he is the true expert when it comes to real-world implementation. 🙏 I am very grateful for his book and look forward to learning from it. PS: The conference itself was amazing and very special to me. I will share more about that soon.