Decentralized Multi-Split Vault using TEE Clusters for Fault-Resistant Tor Onion services

Tor Onion services enable anonymous communication by decoupling network identity from physical location. However, traditional implementations rely on a single, alwaysonline server that centralizes cryptographic keys and service logic, creating a critical security and availability bottleneck. This work introduces a distributed TEE-based multi-split vault architecture that eliminates single points of failure through a novel design, i.e., split-vault design using Intel SGX, AMD SEV, and Shamir's Secret Sharing. The system keeps data private, safe, and accessible even if there is a partial breach, such as a vault breach or a TEE platform failure, by stopping unauthorized decryption, forged writes, and metadata leaks. A 2-of-3 Raft consensus protocol makes it even harder to link traffic, protects against platform-specific side-channel attacks, and ensures that malicious administrators cannot compromise the system. The proposed system has been tested and shown to be highly fault-tolerant and to support distributed trust, with minimal performance overhead. This makes it useful for real-world Tor deployments and allows for dynamic, interactive content. The proposed method significantly enhances the security and resilience of Onion services against advanced threats.