When Blockchain Meets Tor: Enabling Automatically Distributed Blind Choosing of Relay Nodes in Anonymous Communication

Anonymous communication services represent a critical class of privacy-preserving infrastructure within the service computing paradigm, where trustworthiness, resilience, and quantifiable quality-of-service (QoS) are foundational requirements. Tor-the most widely deployed anonymous communication service-relies on a centralized Directory Authority (DA) component that functions as a monolithic trust anchor. This architectural choice introduces severe service-level vulnerabilities: single points of failure degrade availability (QoS), metadata exposure compromises privacy (a core service attribute), and centralized control enables censorship-directly violating service computing principles of decentralization, fault tolerance, and user-centric trust. We propose AuDi-BCoRN (Automatically Distributed Blind Choosing of Relay Nodes), a service-native re-architecture that transforms Tor's directory layer into a decentralized, self-governing service ecosystem grounded in the tenets of service computing. By integrating blockchain as a decentralized trust service and using smart contracts for automated service coordination, AuDi-BCoRN eliminates centralized dependencies while closely matching native Tor performance: on a 3% tornettools-generated Tor topology, the empirical CDFs of TTFB, latency, and throughput are nearly indistinguishable from Tor beyond the median, while demonstrably strengthening service integrity against DoS, censorship, and traffic-analysis threats.