DT-Share: A State-Bound Access Control Middleware for High-Churn Distributed Data Sandboxes

Abstract

Abstract Hybrid architectures in permissioned blockchains combining on-chain policies with Threshold Proxy Re-Encryption (TPRE) suffer from a structural audit gap: cryptographic enforcement is decoupled from the ledger's state. This allows Byzantine proxies to execute unaccountable data transformations (ghost requests). Furthermore, traditional TPRE access revocation incurs O(N) linear overhead, creating a scalability bottleneck.To address these flaws, we propose DT-Share, a state-bound access control middleware. By leveraging a novel State-Bound Evidence mechanism, DT-Share cryptographically anchors TPRE outputs to the global ledger epoch. This transforms access revocation from an O(N) key-management task into a constant-time O(1) ledger state transition.A full-stack implementation using Hyperledger Fabric and IPFS demonstrates that DT-Share guarantees strict accountability with negligible overhead. Under high-concurrency workloads, it exhibits an elasticity inversion phenomenon, adaptively scaling throughput during bursty requests to provide a highly scalable, Byzantine-resistant middleware for distributed consortia.