vObliChain: Securing satellite networks with verifiable oblivious search over blockchain databases

The rapid development of space-based computing, supported by integrated space–air–ground 6G infrastructure and national initiatives like Sky-Earth Integrated Computing, is driving the formation of large-scale, intelligent satellite networks. These systems continuously generate petabyte-scale, heterogeneous satellite data, demanding secure, real-time, and trustworthy data sharing services. Blockchain technology, with its properties of decentralization, immutability, and cryptographic auditability, provides a promising foundation for satellite data governance. However, enabling efficient, privacy-preserving, and verifiable data retrieval over blockchain-based satellite systems remains a fundamental challenge. To address this, we propose vObliChain—a verifiable and oblivious search framework tailored for large-scale satellite blockchain networks. vObliChain integrates searchable encryption with a two-level indexing and verification design. At the global level, an oblivious map (OMAP) supports forward-private, sub-linear block localization. At the local level, an optimized Merkle Patricia Trie (MPT) enables efficient intrablock search. A dual-layer proof mechanism ensures correctness and completeness via Merkle proofs and multiset-hash-based digest lists. Meanwhile, dual-layer encryption and SGX-based trusted execution protect data confidentiality and query privacy. We formally analyze the security properties of vObliChain and implement a prototype using real-world satellite metadata. Experimental results show that vObliChain outperforms existing verifiable blockchain search schemes, while providing strong privacy guarantees. This work lays a foundation for secure, scalable, and verifiable satellite data sharing in next-generation space-based information systems.