Privacy Preserving Lightweight Searchable Encryption for Cloud Assisted e-Health System

Large number of health organizations have started making use of cloud assisted technologies to collect, share and process medical records. Wireless Body Area Sensor Network (BASN) is employed to record information such as blood pressure, heart rate, etc from the patient's body. The collected data is stored on the cloud such that it could be shared among different users for providing better services. However, there are many security challenges in using cloud backed large scale commercial e-health applications. The basic challenge is to maintain confidentiality of data while it is transmitted over the communication channel, or stored and searched by cloud provider. Further, unauthenticated or malicious sensor could upload the fake patient reports to the cloud. These problems are amplified due to resource constrained devices like sensor nodes of BASN as resource exhaustive security operations are not affordable by them. Moreover, a malicious cloud could also violate the privacy of a user by tracking its cloud usage pattern. In this paper, we propose a lightweight and secure searching scheme over encrypted data for e-Health environment. We make use of hybrid encryption scheme including symmetric encryption and optimized identity-based encryption (IBE) scheme to ensure data confidentiality over communication channel and for enhancing cloud privacy. Further, due to its lightweight nature, it is affordable for constrained sensors with minimal computation and storage resources. Implementation results confirm the lightweight nature of our proposed scheme.