Blockchain-Based Access Control Scheme for Secure Shared Personal Health Records over Decentralised Storage

Abstract

Blockchain technology provides a tremendous opportunity to transform current personal health record (PHR) systems into a decentralised network infrastructure. However, such technology possesses some drawbacks, such as issues in privacy and storage capacity. Given its transparency and decentralised features, medical data are visible to everyone on the network and are inappropriate for certain medical applications. By contrast, storing vast medical data, such as patient medical history, laboratory tests, X-rays, and MRIs, significantly affect the repository storage of blockchain. This study bridges the gap between PHRs and blockchain technology by offloading the vast medical data into the InterPlanetary File System (IPFS) storage and establishing an enforced cryptographic authorisation and access control scheme for outsourced encrypted medical data. The access control scheme is constructed on the basis of the new lightweight cryptographic concept named smart contract-based attribute-based searchable encryption (SC-ABSE). This newly cryptographic primitive is developed by extending ciphertext-policy attribute-based encryption (CP-ABE) and searchable symmetric encryption (SSE) and by leveraging the technology of smart contracts to achieve the following: (1) efficient and secure fine-grained access control of outsourced encrypted data, (2) confidentiality of data by eliminating trusted private key generators, and (3) multikeyword searchable mechanism. Based on decisional bilinear Diffie–Hellman hardness assumptions (DBDH) and discrete logarithm (DL) problems, the rigorous security indistinguishability analysis indicates that SC-ABSE is secure against the chosen-keyword attack (CKA) and keyword secrecy (KS) in the standard model. In addition, user collusion attacks are prevented, and the tamper-proof resistance of data is ensured. Furthermore, security validation is verified by simulating a formal verification scenario using Automated Validation of Internet Security Protocols and Applications (AVISPA), thereby unveiling that SC-ABSE is resistant to man-in-the-middle (MIM) and replay attacks. The experimental analysis utilised real-world datasets to demonstrate the efficiency and utility of SC-ABSE in terms of computation overhead, storage cost and communication overhead. The proposed scheme is also designed and developed to evaluate throughput and latency transactions using a standard benchmark tool known as Caliper. Lastly, simulation results show that SC-ABSE has high throughput and low latency, with an ultimate increase in network life compared with traditional healthcare systems.

Addressing the Challenges of Electronic Health Records Using Blockchain and IPFS

“…After verification, the private key is destroyed by the verifier’s application. In Healthchain [ 37 ], Chenthara et al employed special public-key cryptography for encrypting the data in the IPFS off-chain storage [ 81 ]. The system allows only the permissioned or authenticated users to access the record for a particular session.…”

“…The system allows only the permissioned or authenticated users to access the record for a particular session. Patients have complete control of granting and revoking access to their medical records to preserve the confidential nature of health data [ 41 , 47 , 60 , 67 , 81 ].…”

“…Demir and Kocak [ 75 ] proposed a general framework for sharing critical documents not limited to the EHR domain using blockchain and IPFS. Because the medical files would be stored on public IPFS nodes, the system will use access control and encryption to ensure the confidentiality of the health records [ 81 , 101 ].…”

Securing medical records based on inter-planetary file system and blockchain

“…A unique identifier called Content Identifier (CID) is generated using a cryptographic hash function [26]. IPFS relies on DHT (Distributed Hash Table) which is a distributed system that maps CID to peer addresses that have the content (key-value mapping, CID to IP address/port) [27]. For instance, "ipfs://x" is a request to access a file with CID "x" which query the DHTs to retrieve all peers that have that particular CID.…”

Implementation of Electronic Health Record and Health Insurance Management System using Blockchain Technology

“…Blockchain is the next big thing in healthcare and it will revolutionize how it is supplied and administered. The fundamental issue is information asymmetry, which means that not everyone has the same easy access to the data [5]. Blockchain and smart contracts safeguard data, increase interoperability, and allow numerous entities to access the medical information that makes up the EHR by providing a secure distributed network, a shared ledger, and the ability to add independent blocks of medical transactions [3].…”