This book constitutes the revised selected papers of the 10th International Workshop on Data Privacy Management, DPM 2015, and the 4th International Workshop on Quantitative Aspects in Security Assurance, QASA 2015, held in Vienna, Austria, in September 2015, co-located with the 20th European Symposium on Research in Computer Security, ESORICS 2015. In the DPM 2015 workshop edition, 39 submissions were received. In the end, 8 full papers, accompanied by 6 short papers, 2 position papers and 1 keynote were presented in this volume. The QASA workshop series responds to the increasing demand for techniques to deal with quantitative aspects of security assurance at several levels of the development life-cycle of systems and services, from requirements elicitation to run-time operation and maintenance. QASA 2015 received 11 submissions, of which 4 papers are presented in this volume as well.