He studied computer science and philosophy of science, technology and society at the University of Twente, and wrote his interdisciplinary PhD "La volonté machinale: understanding the electronic voting controversy" at the Radboud University Nijmegen. Pieters’s research focuses on cyber security risk management in complex systems. He works with qualitative and quantitative socio-technical security models, attack models, and attack graphs, to discover and prioritise weaknesses, and evaluate countermeasures. In relation to such decision support, he is also interested in the ethics of cyber security and in the integration of security and safety. He published on electronic voting, verification of security properties, cyber risk management, and philosophy and ethics of information security.