# A Security-Oriented Data-Sharing Scheme Based on Blockchain
## 2 Related Works
The communicating parties are not fully trusted, and there is still a risk of data leakage. In 2021, [PERSON] et al. [21] proposed a blockchain and IoT-based framework that uses Ethereum smart contracts to develop a transparent, reliable, and tamper-resistant food supply chain. This framework aims to achieve a blockchain-based supply chain data-sharing scheme and ensure secure data sharing and traceability requirements. In 2022, [PERSON] et al. [22] proposed a blockchain-based data-sharing framework for edge data-sharing services between heterogeneous network domains in industrial IoT. This framework introduces a two-layer stacked network topology and an edge computing paradigm, recording all data-sharing activities on a blockchain. [PERSON] et al. [23] designed a blockchain-based data-sharing platform that improves security and privacy by tracking and recording the history of shared data and collecting and storing valid sharing records in the blockchain network. In 2023, [PERSON] et al. [24] proposed a novel blockchain model verification method to enhance the security of blockchain systems. This method integrates the advantages of aspect-oriented analysis and model checking into the blockchain architecture, utilizing Aspect-Oriented Programming (AOP) to analyze and monitor the dynamic behavior of blockchain systems, thereby achieving more effective and efficient verification. All proposed schemes utilize blockchain technology to safeguard data integrity and prevent unauthorized data alterations during sharing. However, it is crucial to recognize that blockchain's inherent openness could increase the risk of data leakage. A robust strategy to enhance data-sharing security is the application of a cryptographic algorithm. In 2021, [PERSON] et al. [25] proposed using the symmetric encryption algorithm AES to encrypt the information intended for sharing. Data in cloud storage are encrypted to ensure secure storage, with blockchain technology providing privacy protection. However, the use of a single key for both encryption and decryption in symmetric algorithms poses a risk of key leakage. Additionally, [PERSON] et al. [26] proposed a Medchain architecture that utilizes a cloud-based proxy server node to re-encrypt patients' private data. Proxy re-encryption ensures patient privacy. For enhanced security, the server is decoupled from the blockchain system, reducing the risk of tampering or unauthorized access from external entities. However, the node remains vulnerable to attacks, which could lead to a single point of failure. [PERSON] et al. [27] introduced a trusted blockchain-based access control scheme focused on security, which addresses the issue of a single point of failure caused by a centralized private key generation. This solution achieves more secure and efficient access control by integrating a decentralized attribute-based encryption algorithm (DABE) algorithm with a private key consensus verification protocol based on zero-knowledge proof. Integrating blockchain technology with data sharing raises a significant concern. In the age of big data, the increasing volume of data on the blockchain requires continuous expansion. Furthermore, the immutability of this data intensifies the storage demands placed on the blockchain. To address this issue, research has explored the integration of blockchain with cloud computing, advocating for the storage of raw data off-chain to reduce storage pressures. However, cloud-based data-sharing systems face the challenge of a'single point of failure', as third-party cloud providers, being semi-trusted, introduce complexities in ensuring robust data-sharing security. In 2020, [PERSON] et al. [28] introduced a reliable cross-domain authentication mechanism for the Internet of Things (IoT) based on master-slave chaining. This architecture utilizes a master-slave blockchain configuration to facilitate distributed cross-domain authentication. The slave chain stores shared data, with its hash value securely anchored on the master chain to prevent tampering.