A Lightweight IoT Data Security Sharing Scheme Based on Attribute-Based Encryption and Blockchain

The accelerated advancement of the Internet of Things (IoT) has generated substantial data, including sensitive and private information. Consequently, it is imperative to guarantee the security of data sharing. While facilitating fine-grained access control, Ciphertext Policy Attribute-Based Encryption (CP-ABE) can effectively ensure the confidentiality of shared data. Nevertheless, the conventional centralized CP-ABE scheme is plagued by the issues of key misuse, key escrow, and large computation, which will result in security risks. This paper suggests a lightweight IoT data security sharing scheme that integrates blockchain technology and CP-ABE to address the abovementioned issues. The integrity and traceability of shared data are guaranteed by the use of blockchain technology to store and verify access transactions. The encryption and decryption operations of the CP-ABE algorithm have been implemented using elliptic curve scalar multiplication to accommodate lightweight IoT devices, as opposed to the more arithmetic bilinear pairing found in the traditional CP-ABE algorithm. Additionally, a portion of the computation is delegated to the edge nodes to alleviate the computational burden on users. A distributed key management method is proposed to address the issues of key escrow and misuse. This method employs the edge blockchain to facilitate the storage and distribution of attribute private keys. Meanwhile, data security sharing is enhanced by combining off-chain and on-chain ciphertext storage. The security and performance analysis indicates that the proposed scheme is more efficient and secure.