This book constitutes the proceedings of the 5th International Conference on Principles of Security and Trust, POST 2016, which took place in Eindhoven, The Netherlands, in April 2016, held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2016.

The 12 full papers presented in this volume were carefully reviewed and selected from 35 submissions. They were organized in topical sections named: information flow; models and applications; protocols.