A blockchain-based and privacy-preserved authentication scheme for inter-constellation collaboration in Space-Ground Integrated Networks

Space-Ground Integrated Networks (SGINs) make it convenient for users to access services anywhere. In the space segment, satellite constellations can cooperate to provide better space services. However, due to the lack of trust among different constellations, communication security and privacy protection are important issues that need to be solved during inter-constellation cooperation. In this work, with recent advances of blockchain, we present a trusted and privacy-preserved authentication scheme for inter-constellation collaboration. To preserve privacy, we design permanent and temporary identities for each satellite. The permanent one is used for inner constellation communication, and the temporary identity is for inter-constellation cooperation, respectively. Meanwhile, satellites generate temporary identities for themselves to avoid privacy leakage. A consortium blockchain is introduced for sharing information among cooperative satellite constellations. Furthermore, to achieve efficient authentication under limited resources, a replica storage node method is proposed, where wellresourced satellites cache the replicated information shared through the blockchain. The replica storage node selection is formulated as an integer programming problem and solved with a branch and bound algorithm. Security analysis, including formal analysis using BAN Logic and informal verification, shows that the proposed authentication scheme is secure against various potential attacks. A comparative analysis among the proposed scheme and other blockchain-based schemes shows that the proposed scheme achieves efficiency in signaling, computation, and communication overheads with more functionality attributes. In addition, evaluations also demonstrate that the proposed on-board caching scheme achieves low communication latency and storage cost.