This PhD position at the University of Twente focuses on developing a reference architecture for privacy-preserving data visiting, a paradigm that allows algorithms to securely access and process data within its native environment. The project is designed to support federated learning, enabling the training of machine learning models without transferring sensitive or large-scale datasets between systems. The research will address key challenges in security, privacy, governance, and performance, while also tackling interoperability and semantic issues associated with heterogeneous healthcare datasets. Practical evaluation will be conducted using healthcare data, a field marked by strict privacy regulations and diverse data standards. Case studies will be performed within the ERDERA EU project, which investigates secure and privacy-preserving methods for sharing rare disease data across European research infrastructures. The project combines architectural modeling with hands-on prototyping to create a blueprint for trustworthy, semantically-aware data visiting infrastructures that can facilitate advanced analytics and AI applications in healthcare. The successful candidate will join the SCS department at the Faculty of Electrical Engineering, Mathematics, and Computer Science (EEMCS), which specializes in semantic modeling, cybersecurity, and service design for trusted digital environments. The department's research includes ontology-driven conceptual modeling, FAIR data stewardship, and model-driven system/service engineering, with applications in healthcare, agriculture, logistics, emergency management, smart cities, and manufacturing. The PhD position offers a full-time appointment for four years, with a qualifier in the first year, and includes a competitive salary, holiday and end-of-year bonuses, pension scheme, flexible working arrangements, generous leave, free access to sports facilities, and family-friendly policies. The candidate will participate in a training programme through the Twente Graduate School, with a tailored education and supervision plan. Applicants should have or be about to obtain a master's degree in computer science or a related field, possess strong analytical and communication skills, and be proficient in English. Non-Dutch applicants must provide proof of English proficiency via IELTS, TOEFL-iBT, or Cambridge CAE-C (CPE). Applications should be submitted online by November 27, 2025, and must include a CV, cover letter, and, if applicable, publications and references. For further information, contact Dr. Claudenir Morais Fonseca at c.moraisfonseca@utwente.nl.