Blockchain technology provides a secure and reliable platform for managing data in various application areas, such as supply chain management, multimedia, financial sector, food sector,Internet of Things (IoT), healthcare, and many more. The recent emergence of blockchain with IoT provides significant growth in the healthcare industry to improve security, privacy, efficiency, and transparency with more business opportunities. Nevertheless, conventional healthcare schemes suffer from various security attacks like collusion, phishing, masquerade, etc. Therefore, a privacy-preservingDistributed Application (DA)is proposed in this paper using blockchain technology to create and maintain healthcare certificates. Here, the distributed application provides an interface between the blockchain network and system objects like healthcare centers, verifiers, and regular authorities to generate and issue medical documents. In addition, it also ensures security by specifying rules using various smart contracts. To evaluate the performance of the proposed scheme, various experimental tests are conducted using the Etherscan tool for measuring operation cost, latency, and processing time. Here, the efficiency of the proposed system is also compared to the existing systems in terms of latency, throughput, and response time. The experimental results and comparative analysis show that the proposed work is more efficient than the existing techniques.

Nowadays, medical certificates are very important for many users as they want to avail health benefits like tax purposes, insurance claims, legal procedures, and many more. Generating, issuing, and maintaining medical certificates remain a significant problem; before the invention of the computer, they were available as hard copies. The digitization of medical certificates and documents leads to potential security issues, such as forging of certificates risks the privacy of healthcare documents. Moreover, individuals still need to be physically present and wait at the issuing healthcare centers to get the certificates. Currently, the infrastructure of any healthcare industry connects the Internet of Things (IoT) devices and application software that communicates with the information technology systems. Blockchain technology with IoT can significantly affect the healthcare industry by improving efficiency, security, transparency, and can provide more business opportunities. Therefore, a privacy-preserving technique has been proposed in this article for IoT-based healthcare systems using blockchain technology. The proposed architecture provides an interface between the users and healthcare centers to generate and maintain healthcare documents. Furthermore, the proposed scheme ensures security by specifying rules with a smart contract. Results and discussion show that the proposed scheme is more efficient than the existing schemes.

The cab-sharing system provides a platform for drivers and riders with shared trip services, providing significant benefits, such as decreasing traffic congestion, reducing travel costs, and limiting energy consumption, which improve the business of transportation. However, existing cab-sharing systems mainly depend on the centralized authority to provide many services, increasing privacy concerns and facing the single point of failure issue. Also, these systems expose drivers’ or riders’ locations and personal information that increase security issues, and charge high fees for services due to the involvement of third-party providers. Therefore, this paper proposes a decentralized and secure cab-sharing system to provide ride-sharing services using blockchain technology without any trusted third party. The proposed system uses the blockchain structure to preserve the driver’s or rider’s information, such as personal details, travel price, pickup or drop-off locations, departure or arrival date, and time. Furthermore, it implements the reputation feature to rate drivers and riders based on their travel history or behaviors without any centralized authority that allows users to select them based on their past experiences on the system. The proposed architecture is deployed using the Ethereum platform and functionality is designed using smart contracts. The performance evaluation and experimental results show that the proposed system requires low computational overheads and provides an efficient cab-sharing platform.