John Sotiropoulos is the Founder & Principal Consultant of Deep Cyber Ltd (deepcyber.ai), safeguarding national-scale AI programmes across government, healthcare, and finance. He co-leads the OWASP Agentic Security Initiative, chairs the OWASP Top 10 for Agentic Applications, and is a Board member for the OWASP GenAI Security Project. More recently he founded the OWASP Quantum Security Project.

John liaises with national cybersecurity agencies and has authored the UK Government's Implementation Guide to the AI Cyber Security Code of Practice, which has since evolved into the ETSI EN 304 223 global standard. He sits on the ETSI SAI technical committee shaping global standards for secure AI and agentic systems. He was Highly Commended for Security Professional of the Year at the 2025 UK IT Awards, and is the author of the best-selling book Adversarial AI Attacks, Mitigations, and Defense Strategies as well as the briefing When Agents Go to War: Military AI, Governance, Competition, and Strategic Advantage in the Autonomous Era.