Introduction
Work Experience
Technical Skills
David Büngener
Security expert with 10 years of experience: I find security weaknesses and fix them myself — from software down into the devices. Solutions that stay.I'm a security expert with 10 years of experience in highly sensitive IT systems. My specialty: finding security weaknesses and fixing them myself — from the software down deep into the devices. Unlike consultants who only test and disappear, I leave behind solutions that stay with you.
Work Experience
Ongoing engagements
Tetraguard
2026 - Present- Designed an extra security layer that sits between the Windows login and the Microsoft cloud service and confirms the sign-in through a second, independent channel (for example your phone). The login key is split and encrypted so that neither side can see the other — and if anything goes wrong, the door stays locked.
- Built the core of the system, which can plug in different confirmation methods (phone code, sign-in app, and more) and runs over a secure, encrypted connection — backed by many automated tests.
- Hardened the system thoroughly against attacks: I systematically worked through where attackers could strike and built in matching protections — among them against reusing intercepted login data and against insecure default passwords, plus complete logging.
Atflow | MeineZeit
2026 - Present- Developed and enterprise-hardened the MeineZeit desktop installer (Electron/NSIS) for deployment via SCCM, Intune, and GPO in regulated environments — including SYSTEM-context detection for correct per-machine installation under %PROGRAMFILES%.
- Implemented automated test pipelines (71+ tests / 558+ assertions) for installer quality and regression safety in silent/unattended installations plus system-context validation.
- Architected per-machine and per-user installation paths, SYSTEM-context detection, and certificate-based code signing (Azure Trusted Signing) for enterprise readiness.
KiDara
2024 - Present- E2E-encrypted chat via Matrix/Synapse (Free tier), self-hosted homeserver setup, federation disabled, TTDSG-compliant.
- Tiered subscription model (Free/Organisiert/Organisiert+) with family plan, Stripe/Mollie, feature gating, B2B lawyer dashboard.
- Full-stack: Next.js + FastAPI + PostgreSQL/pgvector, Docker Compose production deployment, CI/CD, GDPR/RDG-compliant.
Completed Projects
Königszahn
2025 - 2026- Created security documentation that meets healthcare requirements and made sure software updates are installed reliably.
- Advised on and operated secure IT systems for handling especially sensitive data.
amperetta GmbH
2023 - 2024- Developed the control software for the drive of sport boats with a hybrid engine — with high demands on performance, safety, and reliability.
- Built a secure way to supply the devices on the boats with software updates from a distance, without anyone being able to tamper with them.
- Closely linked the electric and combustion engines — with a control system that reacts safely in critical situations and catches errors.
- Built an automated test setup that checks new device software on its own — this was the foundation of my current understanding of security.
Forschungszentrum Jülich
2022 - 2023- Developed systems that capture scientific measurement data in real time — with high demands on accuracy, reliability, and keeping the data unaltered.
- Designed secure technology for important research facilities, where constant availability and complete traceability mattered most.
- Brought many different sensors with various connection types together into one unified software platform.
- Worked closely with scientists to translate their requirements into robust, easy-to-maintain technical solutions.
Technical Skills
Backend & CloudTypeScript (Node.js/NestJS), Python (FastAPI/Scripting), Go, Docker, CI/CD Pipelines, GitHub Actions, Linux Server Administration. SQL/NoSQL data modeling, Apache Kafka, handling large time-series datasets.
Cyber Security (Offensive Mindset)Web App Pentesting (OWASP Top 10), API Hardening, Secure Code Review. Tooling: Burp Suite, SQLmap, Nmap, Metasploit, HTB Lab Environments. Certification path: Candidate for HTB CBBH & CPTS.
Foundational Knowledge (Embedded Heritage)C / C++, hardware interfaces (SPI/I2C/CAN), RTOS. I leverage over a decade of experience in critical infrastructure primarily for low-level security audits and understanding system exploits. Learn more on my Foundation page.