Abstract
It is considered important in the medical care sector to share medical information such as case information. There have been positive moves toward electronic storage and sharing of various data. There have been many studies of systems to realize such services, but the usual approach is to construct a network system of clientβserver type with concentrated information management at one site. In contrast, we are promoting the development of a medical information sharing platform in which information distributed among peers (hospitals) is shared. The P2P configuration has the advantage that the processing load is distributed and a relatively lowβcost system can be created. The keys to creating this platform include the development of a secure information sharing mechanism, and also an efficient retrieval mechanism. This paper presents a security mechanism which was constructed for verification experiments on such a platform. In the design of the security mechanism, the above characteristics of the platform are considered, and an attempt is made to provide content in a practical processing time. The implemented security mechanism is evaluated assuming the processing loads that occur in actual operation, and its effectiveness is demonstrated. Β© 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(11): 49β63, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20466