BCTC-KSM: A blockchain-assisted threshold cryptography for key security management in power IoT data sharing

With the rapid advancement of the manufacturing industry from digital stage to network stage, the massive data generated by the production, consumption and other links in power IoT (PIoT) needs to be analyzed and processed urgently. However, due to the limited storage and computing capacity of PIoT devices, the collected industrial data are usually encrypted and stored in the cloud. Data security will be highly dependent on key security, and it is crucial for data privacy protection in PIoT to securely manage keys. Therefore, this paper proposes a Blockchain-Assisted Threshold Cryptography for Key Security Management in Power IoT Data Sharing (BCTC-KSM). We use the Pedersen threshold secret sharing algorithm off-chain to split the symmetric keys used to encrypt cloud-outsourcing data in PIoT into multiple key fragments and publish them on-chain, and use the ledger technology of blockchain to record the rotation history of each key fragment and its access subjects, and then restrict the user access to the key fragments through attribute access control policies on-chain. Security analysis and experimental results show that the BCTC-KSM can significantly improve the security and availability in PIoT data sharing at a slightly higher time cost than the state-of-the-art cryptography scheme.