HeaL: A blockchain-envisioned signcryption scheme for healthcare IoT ecosystems

The paper proposes a light-weight blockchain (BC)-envisioned scheme HeaL, that ensures secure and trusted exchange of electronic health records (EHR) over open wireless channels, with minimum encryption and signing overheads. HeaL operates in two phases. In the first phase, proximity sensor nodes (PSN) are mounted over the patient to form a wireless body area network (WBAN). The nodes elect a cluster-head (CH) in its vicinity based on resource capability to forward data to gateway sensor nodes (GSN) in WBAN, with EHR meta-information recorded in BC. Then, in the second phase, GSN executes a lightweight signcryption scheme that combines encryption and signing of data among authorized stakeholders. The data is exchanged over open channels and is accessible to authorized personals by fetching secure keys from Inter-planetary file systems (IPFS). The mined information is finally stored as block ledgers in global chain structures to reduce computational overheads. The proposed scheme HeaL is compared against existing schemes in terms of parameters like transaction and signing cost, transactional throughput, and computational and communication costs. In simulation, HeaL achieves an average signing cost and verifying cost of 3.32 seconds (s) and 6.52 s, respectively. For 200 blocks, the mining latency is 3.325 s, compared to traditional schemes with a latency of 7.8 s. The obtained transactional throughput is 142.78 Mbps, compared to traditional 102.45 Mbps. In security evaluation, the computation cost (CC) is 45.80 milli-seconds (ms), and communication cost (CCM) is 97 bytes, which indicates the viability of the proposed scheme against other state-of-the-art approaches.