A HIGH DEGREE OF PATIENT PRIVACY IN PHR PATIENT-CENTRIC MODEL OF HEALTH INFORMATION EXCHANGE USING CLOUD SECURITY TECHNIQUE The objective is to provide solution to the identied issues of: security, key complexity, and user revocation. The system will solve security and key management problem by making use of homomorphic encryption. The goal of the framework is to secure the PHRs and the data outsourced. PHR owners can specify personalized ne-grained role-based access policies during file encryption. The implementation of Attribute-based encryption (ABE) technique is used to achieve ne-grained and scalable data access control for PHRs to encrypt each patient's PHR file.