Privacy-Preserving and Secure Sharing of PHR in the Cloud.

As a new summarized record of an individual's medical data and information, Personal Health Record (PHR) can be accessible online. The owner can control fully his/her PHR files to be shared with different users such as doctors, clinic agents, and friends. However, in an open network environment like in the Cloud, these sensitive privacy information may be gotten by those unauthorized parties and users. In this paper, we consider how to achieve PHR data confidentiality and provide fine-grained access control of PHR files in the public Cloud based on Attribute Based Encryption(ABE). Differing from previous works, we also consider the privacy preserving of the receivers since the attributes of the receivers relate to their identity or medical information, which would make some sensitive data exposed to third services. Anonymous ABE(AABE) not only enforces the security of PHR of the owners but also preserves the privacy of the receivers. But a normal AABE with a single private key generation(PKG) center may not match a PHR system in the hierarchical architecture. Therefore, we discuss not only the construction of the PHR sharing system base on AABE but also how to construct the PHR sharing system based on the hierarchical AABE. The proposed schemes(especially based on hierarchical AABE) have many advantages over the available such as short public keys, constant-size private keys, which overcome the weaknesses in the existing works. In the standard model, the introduced schemes achieve compact security in the prime order groups.