Improving data transmission through optimizing blockchain sharding in cloud IoT based healthcare applications

The rapid progress of blockchain technology is increasingly crucial in healthcare systems, where Electronic Health Records (EHRs) store vital and confidential information. However, these systems are susceptible to security risks like unauthorized access and data breaches. To tackle these issues, a decentralized, tamper-proof, and transparent healthcare network is necessary. According to this fact, the Sec-Health protocol utilizes cryptographic techniques with blockchain and InterPlanetary File System (IPFS) to safeguard EHRs. Despite advancements, managing large files, such as medical imaging data, remains a challenge due to scalability issues and limited research. Introducing sharding has the potential to improve network scalability, but if not configured correctly, it could result in orphan blocks and forks, leading to security vulnerabilities and network delays. To address this, a new sharded blockchain-based protocol called an Adaptive Sec-Health (AdaSec-Health) is proposed, utilizing an Enhanced Coati Optimization Algorithm (ECOA) in high-throughput and low-latency healthcare systems. The ECOA optimizes multiple factors to minimize orphan blocks and forks while balancing Fork Probability (FP) and User Experience (UE). Also, it introduces a cost function to optimize network security-stability tradeoffs. Thus, AdaSec-Health protocol improves the scalability and security of healthcare blockchain systems. The experiments are conducted on the network EIP-1559 using 1000 nodes with 1 to 4 shards to validate the scalability and security of the AdaSec-Health protocol. The results demonstrate that the AdaSec-Health protocol achieves 3280 transactions per second (tps) of mean throughput, 28 s of mean user-perceived latency, 0.47 gas unit of average marginal cost, 36 transactions of average block size, and a 13-second mean interval between blocks for 1000 nodes in 4 shards compared to the other healthcare blockchain systems. In terms of security analysis, AdaSec-Health achieves 7087 tps, 6738 tps, and 6400 tps for simple attacks, camouflage attacks, and observe-act attacks across 20 epochs.