Personal health record (PHR) is a patient’s personal health information where a patient can store and maintain his personal health details in a cloud server which is a third party. Therefore, security and sharing of personal health information is a concern from parties like cloud server and unauthorized users. It is very important for a patient to have full control on their personal PHRs, hence it is important that PHRs have to be encrypted before outsourcing them to cyber service provider. In this paper, analysis of various PHR schemes for encryption is compared and results are analyzed.

Personal Health Record (PHR) in cloud database is stored, manipulated, and shared with users for high value of health care. The challenge is privacy of sensitive personal information and protection of data. In this paper, the attribute entropy key along with signature cryptosystem is proposed to move the data’s stored in third party cloud server in a secure way. In the proposed work, the PHR data is taken as an input and an attribute is selected for which attribute key generated using KEK (Key Encryption Key) algorithm. To secure the generated key, entropy is calculated for PHR data. This key is used to encrypt the PHR data. Then signature based on support value is generated for the PHR data and it is stored with the encrypted data in the cloud. Now, when the users want to access data, decryption is allowed after verification of both generated private key and signature which basically is for data integrity. Once the verifications are successful, then the authorized users are granted permission to access data from the cloud. The results display that the suggested method performs better when compared with other existing methods on parameters like cipher text size, query processing time, communication cost, and decryption time.