I'm Petr Ziegner, a penetration tester based in Prague. I get paid to break into systems and then write up exactly how I did it. Off the clock I put hardware in my hands and find out how far I can actually take it.
Penetration tester, ethical hacker, and someone who has never been able to leave a system alone without poking at it. I've been doing this since 2020, freelance first and professionally since. I write code, tinker with hardware, and build tools that solve problems I actually have.
My main hobby is biomodification. I've got five implants in my hands and I follow human augmentation very closely. Cars and amateur radio are still around in the background, but honestly, mostly in the background.
I test a wide range of targets: web applications, APIs, internal networks, cloud environments, OT and SCADA systems, ATMs, embedded devices, wireless protocols, desktop applications, and hardware. The approach doesn't change much between them. Map the attack surface, find what breaks, document it so it's actually actionable, then help fix it.
I've worked freelance, inside a global consultancy, as a programmer, and as an instructor teaching kids to code. That mix keeps me honest. You test better when you've built the thing you're attacking, and you write better reports when you've had to explain a concept to someone hearing it for the first time.
Outside client work I run p0c.cz, a toolkit of security utilities for practitioners, and sharebin.eu. The rest of my spare cycles go to hardware hacking and human augmentation.
Offensive security engagements covering web applications, infrastructure, APIs, and specialised domains including OT and ICS environments and ATM systems.
Taught programming and technology to children as part of structured educational courses, covering programming fundamentals, robotics, and computational thinking.
Security testing engagements at a large global consultancy. Web application, API, and infrastructure testing across diverse client environments and sectors.
Backend programming, tooling, and system maintenance. Practical development work alongside ongoing freelance security testing.
Internship at Trask Solutions. Exposure to enterprise penetration testing methodology and professional security consulting workflows.
Independent penetration testing and security assessments for clients across the Czech Republic, covering web applications, network security, and security consultancy.
Secondary technical school in Prague focused on IT, computer science, and engineering. Formal foundation in computing, networking, and software development.
University level studies in business, economics, and management. Broadening perspective on enterprise and organisational contexts alongside technical security specialisation.
My personal experience with everyday life using RFID and NFC implants, benefits, lessons, and surprises.
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A practical overview of implant technology, use cases, tools, and how I integrate them into my daily workflow.
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Thoughts on the security implications of implants and how we can protect both our data and our future selves.
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A social media profile and community presence for sharing car content, builds, and automotive passion.
Embedded builds, automation tools, hardware experiments, and practical microcontroller projects.
Companion app for the VivoKey Thermo implant, reading body temperature straight off the chip in my hand.