DS-Chain: A secure and auditable multi-cloud assisted EHR storage model on efficient deletable blockchain

Abstract

In recent years, cloud storage service has widely attracted the healthcare industry. Healthcare organizations are gradually outsourcing the massive-scale electronic healthcare records (EHRs) on cloud paradigm. This specialized cloud-assisted EHR storage architecture facilitates the healthcare organizations with high scalability, flexibility, low-cost operations, and availability to outsourced EHRs. As EHR often contains patients’ sensitive medical information, it becomes essential to ensure the confidentiality and proper secrecy of the outsourced EHRs. Moreover, in the cloud-assisted EHR storage model, the patients no longer have direct control over their outsourced EHRs, which may also cause severe integrity and confidentiality related security issues. Presently, the healthcare industry observes that the emerging immutable blockchain technology properly attains the basic security needs for developing a secure cloud assisted EHR storage framework. Therefore, in this paper, we introduce a model named “DS-Chain”11A preliminary version of this paper was presented at the 22nd IEEE International Conference on High Performance Computing and Communications (IEEE HPCC - 2020).. - a novel deletable consortium blockchain based secure EHR storage model in a multi-cloud paradigm. The model’s key idea is to integrate each EHR outsourcing’s operations into a transaction on a novel efficient consortium blockchain. The proposed model ensures the confidentiality of the EHR’s sensitive medical information and guarantees the proper integrity and correctness of the outsourced EHRs. On the other hand, we employ the collaborative multi-cloud storage model that offers reasonable durability and availability for the outsourced EHRs in the cloud paradigm. Furthermore, we also arrange all the transactions according to their corresponding EHR’s type over the blockchain network, ensuring efficient block deletion. The detailed security analysis with proper formal proofs guarantees the computational intractability of the proposed model. Finally, the extensive performance analysis with test-simulations illustrates the feasibility and practicability of the proposed model.