BSLA: Blockchain-assisted Secure and Lightweight Authentication for SGIN

Abstract Space–Ground Integrated Network (SGIN) can dramatically reduce the coverage restriction of terrestrial networks, and it therefore can meet the high service requirements to achieve low-latency and high-speed global interconnection at anytime and anywhere. Due to the vulnerable communication channels and the limited resources of spatial nodes such as satellite, SGIN is facing many potential threats. As the first gateway of the SGIN, access authentication is an essential step that guarantees the internal security of the network. However, there are some problems in traditional cryptosystem-based authentication mechanisms, such as certificate management problem and centralized key escrow problem. Consequently, designing a lightweight and secure identity authentication protocol can effectively solve the problems faced by SGIN. In this paper, we focus on the private key escrow problem caused by the Private Key Generator (PKG) in Identity-Based Cryptosystems (IBC) mechanism, and propose a Blockchain-assisted Secure and Lightweight Authentication (BSLA) scheme which introduces the blockchain to improve the robustness and reliability of authentication. In BSLA, user’s private key is determined by itself through combining the partial private keys from different PKGs, which prevents the risk of private key exposure caused by single PKG. Meanwhile, the blockchain also serves as the information source for synchronizing user revocation lists to the spatial nodes, which realizes the fast detection of user revocation. We further analyse the security of BSLA and the analytical results show that BSLA can meet various security requirements. In addition, according to the performance evaluation results, BSLA has good scalability in terms of key security strength. Therefore, users can choose different key security strength and make a trade-off between efficiency and security based on the specific requirements.