Quantum Internet Lab

Blockchain satellite constellations are emerging as decentralized, tamper-resistant networks for secure global data exchange and Earth observation applications. Despite their resilience, inter-satellite links (ISLs) and satellite-to-ground communication channels are vulnerable to eavesdropping and future quantum-enabled attacks.  Classical cryptographic protocols, such as RSA and ECC, are increasingly threatened by quantum computing, creating a critical need for quantum-secure blockchain networks in space. Internet Think Tank proposes a scalable architecture integrating Quantum Key Distribution (QKD) with blockchain satellite constellations. Using the entanglement-based E91 protocol over Free Space Optical (FSO) links, the system generates and distributes symmetric keys across ISLs and between satellites and ground-based nodes. The framework addresses key challenges, including orbital-dependent Quantum Bit Error Rate (QBER) across LEO, MEO, and GEO; atmospheric and link-induced disturbances; and the impact of QKD key management on blockchain consensus, block propagation, and data replication. The proposed architecture enhances confidentiality and resilience against both classical and quantum attacks by combining quantum-secure key distribution with blockchain ledger protocols. This framework provides a practical, future-proof solution for secure inter-satellite and satellite-to-ground communications, forming a foundational step toward quantum-resilient global networks and the realization of a space-based quantum internet.

Schematic diagram of entanglement-based quantum secure communication experiment over one thousand kilometers without relay [IMAGE: UNIVERSITY OF SCIENCE AND TECHNOLOGY OF CHINA]