Design and implementation of hybrid consensus mechanism for IoT based healthcare system security

Nowadays, blockchain is emerging as a worthwhile technology for managing sensitive data in electronic healthcare system. It plays an important role in healthcare, medical research and insurance sectors. The consensus algorithms used in blockchain technology for the selection of a new block, provide high-level of security to IoT devices. However, the reliability problem still exists. In the present paper, a blockchain based hybrid consensus mechanism (HCM) is implemented in electronic healthcare system (EHS) to overcome trustworthiness issues. The aim of the proposed HCM is to maintain reputation module on the basis of the block activities. In this context, EHS is designed in four layers namely: system layer, inter-network layer, blockchain layer, and cloud layer. Moreover, HCM consists of five algorithms for creation, validation, fork handling (if any), Merkle tree construction and reward/punishment module respectively. Dev C++ software platform is used for the simulation of the above mentioned HCM algorithms excluding Merkle tree construction which is simulated using conditional contrast high itemset tree. It is observed that all the blocks use same methodology to be the part of a new blockchain network. Moreover, the CPU and memory consumption in the implementation of HCM is always below two percent and about fifty percent respectively as shown in the latency graph. The basic security goal (confidentiality, integrity and availability) is guaranteed with the help of the height of the Merkel tree as well. The performances of the proposed HCM and Proof of X-repute (PoXR) blockchain consensus algorithms are compared with respect to various parameters such as final difficulty, reward and punishment provisions etc. HCM shows superior performance as the final earned reputation is calculated for each block along with the reward and punishment modules during the deployment of blockchain network. In addition, a simple concept of Merkle-tree is opted for providing reward and punishment rather than a set of complex mathematical equations as used in PoXR consensus algorithm.