Slice-aware and cryptographically verifiable PoR for O-RAN systems

The integrity and availability of outsourced data are critical concerns in open and distributed cloud-native infrastructures such as the O-RAN architecture. Existing Proof of Retrievability (PoR) schemes, though effective in traditional settings, are insufficient to address the unique challenges of O-RAN, particularly its heterogeneous slice-specific service requirements, dynamic control loops, and auditability constraints. In this paper, we propose a novel framework that integrates PoR mechanisms into the operational fabric of O-RAN by leveraging its native control architecture. Specifically, we introduce ASAP-CD (Attested Slice-Aware PoR with Challenge Diversity), a dynamic and policy-driven auditing protocol tailored to per-slice service-level agreements, and CPT-PoR (Commitment-Packed Tags for PoR), a lightweight, commitment-based construction that supports efficient designated-verifier auditing without relying on expensive cryptographic primitives. Our design incorporates Trusted Execution Environment (TEE)-based attestation, entropy-bound challenge generation, and real-time PoR coordination via xApps and rApps. Through formal analysis and prototype implementation, we demonstrate that the proposed framework achieves strong correctness, soundness, and retrievability guarantees, while maintaining scalability and modest overhead, making it suitable for deployment in practical O-RAN environments.