Efficient and secure attribute-based heterogeneous online/offline signcryption for body sensor networks based on blockchain

In body sensor networks, both wearable and implantable biosensors are deployed in a patient body to monitor and collect patient health record information. The health record information is then transmitted toward the medical server via a base station for analysis, diagnosis, and treatment by medical experts. Advancement in wireless technology although improves the patient health–monitoring mechanism, but still there are some limitations regarding security, privacy, and efficiency due to open wireless channel and limited resources of body sensor networks. To overcome these limitations, we have proposed an efficient and secure heterogeneous scheme for body sensor networks, in which biosensor nodes use a certificate-less cryptography environment to resolve the key escrow and certificate-management problems, while MS uses a public key infrastructure environment to enhance the scalability of the networks. Furthermore, we design an online/offline signcryption method to overcome the burden on biosensor nodes. We split the signcryption process into two phases: offline phase and online phase. In the offline phase, the major operations are computed without prior knowledge of patient data. While in online phase, the minor operations are computed when patient data are known. Besides, we have used a new hybrid blockchain technology approach for the secure transmission of patient information along with attributes stored in the medical server toward the cloud that provides ease of patient data access remotely from anywhere by the authorized users and data backup in case of medical server failure. Moreover, hybrid blockchain provides advantages of interoperability, transparency traceability, and universal access. The formal security analysis of the proposed scheme is proved in the standard model, and informal security assures that our scheme provides resistance against possible attacks. As compared to other existing schemes, our proposed scheme consumes fewer resources and efficient in terms of processing cost, transmission overhead, and energy consumption.