Beyond Centralized Policy Decision Points: Decentralized Sticky Policy Authorization through Evidence Quorums

2026-09-24

AI Summary

This study addresses the reliance of sticky policy authorization on centralized trusted authorities by proposing a decentralized authorization framework. Within this framework, independent nodes generate local context-signature evidence, and global policy activation is achieved through explicit majority arbitration. Furthermore, a persistent enforcement mechanism is integrated to eliminate single points of failure. By synthesizing distributed architectures, digital signatures, and consensus algorithms, the system ensures tamper resistance throughout the authorization process. Experimental evaluations conducted on an aviation simulation platform demonstrate that the proposed method supports high-concurrency, fault-free operation while achieving fail-safe shutdown. Consequently, this work provides an effective solution for decentralized policy control in high-reliability scenarios.

Abstract

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.

Problem

• sticky policies
• decentralized authorization
• policy decision point
• evidence quorum

Innovation

• Decentralized Authorization
• Sticky Policies
• Evidence Quorum
• Policy Authority Nodes
• Fail-Closed Security