This book presents the most interesting talks given at ISSE 2013 - the forum for the inter-disciplinary discussion of how to adequately secure electronic business processes. The topics include:- Cloud Security, Trust Services, eId & Access Management- Human Factors, Awareness & Privacy, Regulations and Policies- Security Management- Cyber Security, Cybercrime, Critical Infrastructures- Mobile Security & ApplicationsAdequate information security is one of the basic requirements of all electronic business processes. It is crucial for effective solutions that the possibilities offered by security technology can be integrated with the commercial requirements of the applications. The reader may expect state-of-the-art: best papers of the Conference ISSE 2013.