Continued advances in science and technology and general improvements in environmental and social conditions is extending the population's life expectancy with the consequence that a person can undergo many episodes of healthcare during lifetime. In this context, the Electronic Health Record (EHR) represents a fundamental tool to support treatment continuity, education and research. The economic restrictions in healthcare and the need to increase efficiency in term of cost/effectiveness ration could lead institutional organizations to choose cloud solutions to host the EHR. In this paper, a cloud infrastructure architecture, focus on the EHR and based on SOA (Service Oriented Architecture) paradigm, which is able both to completely support technical, semantic and process interoperability, and to guarantee security, is proposed. In order to achieve this goal, the indications and the standards proposed by Healthcare Services Specification Project (HSSP) was adopted. Different situations can be managed by the proposed architecture and are described: the user access to an encrypted resource in EHR, the availability of EHR content for external Decision Support Systems, the update of EHR content, the management of semantic of clinical data exchanged among distributed healthcare organizations. Finally, the authors propose a discussion on the proposed solution.