Privacy is a very important issue when storing electronic medical records. According to the definition set out in the Health Insurance Portability and Accountability Act (HIPPA), the confidential section of the electronic medical record needs to be protected. Thus, a mechanism to protect the patient’s privacy is needed during electronic medical record exchange and sharing. The privacy protection mechanism can be categorized into four types, namely anonymity, pseudonymity, unlinkability, and unobservability. In previous research in this area, mathematical conversions and cross reference tables have been utilized to conceal the confidential part of the electronic medical record to achieve privacy protection. However, it is harder to use these methods with respect to the unlinkability and unobservability mechanisms. Thus, this paper tries to improve on this aspect, and improves the unlinkability mechanism between the patient and the electronic medical record. Cloud computing is known for its fast computation capability and provides large storage space. Through cloud computing, the electronic medical record system in a hospital can be integrated, to facilitate the exchange and sharing of electronic medical records, and to provide smaller hospitals or clinics that have fewer resources with adequate electronic medical record storage space.
Keywords: Electronic Medical Record, Cloud Computing, Privacy, Security, Anonymity