Beyond Centralized Policy Decision Points: Decentralized Sticky Policy Authorization through Evidence Quorums
Researchers present SPEAR-Q, a decentralized sticky-policy system that authorizes access through signed evidence quorums.
Researchers present SPEAR-Q, a decentralized sticky-policy framework that replaces a central Policy Decision Point with independent Policy Authority Nodes. Nodes evaluate the active policy using local context, consent, and risk data, then issue signed authorization evidence; a strict majority decides Permit or Deny, and a committed policy activates only after a majority applies it. On the Airbus Cyber Security Simulation Platform, a MIMIC-IV healthcare workload completed all 9,000 requests without execution failure or timeout. Sub-quorum false-Permit evidence could not release resources, and authorization failed closed when too few nodes were reachable.
- Independent Policy Authority Nodes issue signed authorization evidence from local context.
- A strict-majority quorum decides Permit or Deny and activates committed policies.
- Tested on Airbus's simulation platform using a MIMIC-IV healthcare workload.
- All 9,000 requests finished; sub-quorum false permits stayed fail-closed.
Full article243 words · extracted from arxiv.org · click to collapse
Sticky policies remain attached to protected data so that access restrictions can persist across systems, yet request-time authorization often still depends on a centralized Trusted Authority or Policy Decision Point (PDP). This paper presents SPEAR-Q, a decentralized framework in which independent Policy Authority Nodes (PANs) evaluate the active sticky policy using local context, consent, and risk information and generate signed authorization evidence. A strict-majority Evidence quorum determines the global Permit or Deny decision, while a committed policy becomes active only after the required PAN majority applies it. SPEAR-Q was deployed across physically separated hosts in the Airbus Cyber Security Simulation Platform and evaluated using a healthcare workload derived from MIMIC-IV. Across 9,000 performance requests, all requests completed without execution failure or timeout. Latency increased and throughput saturated as cluster size and concurrency grew, with PAN evidence waiting and PAN-local processing dominating under load and credential validation forming the main PAN-side cost. Policy-activation experiments confirmed majority-based activation. Quorum experiments showed that correctly signed false-Permit evidence from fewer compromised PANs than the required quorum could not produce a global Permit or resource release, while authorization remained fail-closed when reachable PANs fell below the required quorum. Compared with prior approaches that decentralize policy management, credential authority, or threshold-based release separately, SPEAR-Q integrates persistent sticky policy enforcement, independent request-time evidence, majority-based policy activation, and explicit quorum-bounded authorization within one decentralized framework. Under the evaluated conditions, SPEAR-Q supports decentralized sticky-policy authorization without relying on a centralized decision authority.
Text extracted automatically; images, tables and formatting may be missing. Original: https://arxiv.org/abs/2609.29308