Research on Blockchain-based Security Sharing Algorithm of Social Assistance Data in Internet of Things

With the in-depth application of Internet of Things technology in the field of social assistance, the security issue of data sharing has become increasingly prominent. In order to solve the risks of data leakage and tampering in traditional centralized management, this paper proposes a security sharing algorithm for IoT social assistance data based on blockchain and smart contracts. By evaluating different blockchain types in simulation experiments, the results show that private chains perform best in terms of data transmission time and processing power, alliance chains have the highest security score, and hybrid chains achieve a balance between performance and security. Further experiments show that smart contracts significantly improve the efficiency of data sharing, with an intermediary cost saving rate of more than 50% and a maximum contract execution efficiency of more than 20 times per second. In terms of data encryption algorithms, AES has the shortest processing time, RSA has the most stable performance under high security levels, and SM2 consumes more than 65% of CPU in high data volume scenarios, which is costly. In terms of safety score, SHA-256 has the highest score, with an anomaly detection rate of 95%. This study verifies the feasibility and superiority of blockchain combined with smart contracts in ensuring the safe sharing of social assistance data in the Internet of Things, and provides theoretical and practical support for the intelligent and credible construction of social assistance systems in the future.