Due to its legal, ethical, social, and psychological implications, the personal information dealt with in health-related documentation and information systems is highly sensitive and must be recorded, processed, stored and communicated in a trustworthy way. Such documentation and information systems might establish comprehensive Electronic Health Care Record (EHCR) systems or partial aggregation of such data as done, e.g., in the context of clinical studies. Increasingly, such systems are based on the Internet technology. They have to meet approved and emerging protocols and standards of the domain. Within the European HARP project, the HARP Cross-Security Platform has been specified and implemented as an open transparent middleware for providing enhanced services for communication security but especially for application security such as policy enforcement and authorisation of applications. The generic solution has been demonstrated for a multicentric quality assurance study in paediatric endocrinology.