Blockchain-based privacy preservation framework for healthcare data in cloud environment

The storage of Electronic Health Records (EHRs) on mobile cloud environments has undergone a paradigm shift in recent years, with mobile devices integrating with cloud computing to improve medical data transfers between patients and healthcare providers. This sophisticated paradigm allows for minimal operational costs, significant flexibility, and the use of electronic health records (EHRs). However, for e-health systems, this new paradigm poses concerns regarding data privacy and network security. It's a challenging problem to exchange EHRs consistently among mobile users while maintaining high-security levels in the mobile cloud. It's a challenging problem to exchange EHRs consistently among mobile users while maintaining high-security levels in the mobile cloud. Here, this paper intends to introduce a novel blockchain technology for secure health data in the cloud, which aids in ensuring authentication and offers integrity to medical records. Here, blockchain with optimal encryption is deployed via an improved blowfish model that also guarantees authentication features. Further, the optimal key generation is carried out by a new approach termed as Elephant Herding Optimization with Opposition-based Learning (EHO-OBL). Thus, the data integrity is maintained by the developed approach, and at last, the supremacy of the presented approach is proved concerning various measures. Accordingly, the key generation time of the proposed method has attained less value, and it was 51.04%, 91.48%, 92.64%, 91.48%, 89.99%, 91.06% and 91.48% better than traditional Blowfish, Rivest-Shamir-Adleman (RSA), Advanced Encryption Standard (AES), Elliptic-Curve Cryptography (ECC), Elephant Herding Optimization (EHO), Moth-Flame Optimization (MFO) and Whale Optimization (WOA) models, for file size of 10 kb.