Abstract: Cloud computing is obtaining popularity because it provides various on demand services which is location independent. Cloud user can store their data on cloud server remotely. Most of them are from different trust domains. Thus cloud data security and privacy becomes critical task. Before storing the data on the cloud server, the data can be encrypted. Attribute-based encryption technique is a public key encryption which enables access control over encrypted data using different access policies and ascribed attributes. Personal health record (PHR) is an emerging health information exchange model, which is always outsourced to be stored on third party, such as cloud server. Before storing the Personal Health Information of Patients and Doctors the attribute based encryption is applied. A public auditing scheme is used which audits the tampered data on the cloud server. This scheme can totally releases the burden of PHR users about storing and maintaining their data on cloud server.

Keywords: Cloud storage, regenerating codes, public audit, privacy preserving, ABE, AES.