A Hierarchical Certificateless Aggregate Signature Scheme for Secure and Efficient Authentication in <scp>SAGIN</scp>

ABSTRACT Space–air–ground integrated networks (SAGIN) provide ubiquitous connectivity for large‐scale internet of things (IoT) applications by integrating satellite, aerial, and terrestrial networks. However, secure and efficient data authentication in SAGIN remains challenging due to network heterogeneity, dynamic topology, and resource‐constrained devices. Traditional public key infrastructure based (PKI‐based) schemes incur high certificate management overhead, while identity‐based approaches suffer from key escrow, limiting their applicability in SAGIN environments. This paper proposes a hierarchical lightweight certificateless aggregate signature scheme for secure data authentication in SAGIN. In the proposed scheme, IoT devices generate lightweight certificateless signatures, which are hierarchically aggregated at unmanned aerial vehicles and high‐altitude platforms without performing pairing operations. The final aggregated signature is verified at powerful satellite or ground control stations, significantly reducing computation and communication overhead. Security analysis shows that the scheme is existentially unforgeable under adaptive chosen‐message attacks and resistant to pollution attacks. Performance evaluation through theoretical analysis and simulation demonstrates low overhead, constant‐size aggregated signatures, and good scalability, making the proposed scheme suitable for large‐scale SAGIN‐enabled IoT systems.