Enabling Security in Healthcare IoT System Using Blockchain with Efficient Consensus Protocols and Smart Contracts

Electronic Medical Records (EMRs) in hospitals are generally handled by a centralized cloud provider. However, it creates one solitary area of vulnerability, and who are the real owners may lose track of them. To protect the sharing of EMRs among various entities involved in the smart healthcare system, this study seeks to build a smart contract-based access control system on top of a distributed ledger with blockchain. For this, we recommend using smart contracts in four different ways for user authentication. In the proposed system, the hashes of the EMRs are created and added to the Ethereum blockchain. The EMRs themselves are encrypted and saved in the cloud utilizing the cryptographic functions of Elliptic Curve Cryptography (ECC) and Edwards-Curve Digital Signature Algorithm (EdDSA), considering both the massive volume of patient data and the ledger's block size. Performance evaluation with a private Ethereum system is used to observe how well the recommended access control architecture works in the real-time smart healthcare system. Results show that the proposed model outperforms the existing schemes.