Towards secure and trusted collaboration environment for European public sector

e-Business and e-Government implementations are becoming more and more widespread with growing number users depending on availability, accuracy and security of such e- Services. The users must be able to trust these services, otherwise they will be reluctant to embrace the new opportunities and will not be able to reap the potential benefits. In addition, the end users wish to use the e-services in the simplest way possible and to have them "on tap" 24x7 as other conventional utilities. For this to become possible, a robust interoperability fabric among the involved institutions needs to be established. This means having a lot of collaborative interactions invisible to the end-user (a business or an individual citizen) in order to fulfill the promise of e-Services. Such interactions become more complex when the organizations belong to different countries, act according different laws in different languages. This paper presents the work being done to create an efficient, secure and trusted interoperability framework for public sector agencies of European Union member countries.