Cross-Domain Authentication Scheme Based on Distributed Two-Layer Collaborative Blockchains for Cyber-Physical Power Systems

Secure information exchange of the devices among different domains for cyber-physical power systems (CPPSs) is important yet challenging. Conventional blockchain-based authentication schemes generally adopt single blockchain and signature algorithm, only achieving intradomain or interdomain authentication with lower efficiency, and always failing to meet the confidentiality requirement during information interaction in CPPSs. To address these issues, this article proposes a cross-domain authentication scheme based on distributed two-layer collaborative blockchains for CPPSs. First, a two-layer-blockchain collaborative authentication architecture is designed, deploying edge servers and taking into account the distributed characteristic of CPPSs. Second, a signcryption algorithm is developed by combining elliptic curve cryptography (ECC) with certificateless cryptography (CLC), which guarantees both the confidentiality and unforgeability of the block information simultaneously. Furthermore, upper-layer alliance blockchain and lower-layer private blockchain are formed and interact collaboratively via index and Merkle proof, achieving intradomain and interdomain authentication with higher efficiency. Finally, a security analysis and experimental results are presented to superiorly demonstrate the security features and performance in comparison to other schemes in literature.