This PhD position at Radboud University focuses on digital privacy and security, aiming to strengthen the protection of billions of internet users. The successful candidate will join the Digital Security group within the Institute for Computing Sciences, working on the NWO Vidi-funded Web Security and Privacy Observatory (WeSPO) project under the supervision of Dr Gunes Acar. The research addresses critical threats in online privacy and security, including malicious advertising, digital skimming, and stealthy online tracking. By leveraging recent advances in machine learning and browser automation, the project seeks to develop effective tools, techniques, and datasets to combat these threats. The PhD candidate will play a central role in the Observatory, contributing to pioneering research with significant societal and scientific impact. Collaboration opportunities exist both within the group and internationally. The position includes a teaching load of up to 10%. Applicants should hold or be close to completing an MSc in computer science or a related field, possess strong knowledge of web technologies, and have experience in Python and JavaScript. Experience with machine learning models is preferred, and candidates should be motivated to publish at top-tier venues. The employment contract is for 1.5 years initially, extendable to 4 years upon positive evaluation, with a starting salary of €3,059 per month, rising to €3,881 in the fourth year. Additional benefits include holiday allowance, end-of-year bonus, extra annual leave, dual career coaching, pension plan, and discounts on sports and cultural activities. The Digital Security group is one of the largest in the Netherlands, focusing on cryptography, privacy, and cyber security, and is part of the interdisciplinary Radboud iHub. The Faculty of Science at Radboud University is internationally oriented and committed to groundbreaking research and excellent education. The application deadline is 23 November 2025, with interviews scheduled for 27 November and a preferred start date of 1 February 2026. Applications should be submitted online, addressed to Dr Gunes Acar, with all required documents included.