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Monolithic control plane verification cannot scale to hyperscale network architectures with tens of thousands of nodes, heterogeneous network policies and thousands of network changes a day. Instead, modular verification offers improved scalability, reasoning over diverse behaviors, and robustness following policy updates. We introduce Timepiece, a new modular control plane verification system. While one class of verifiers, starting with Minesweeper, were based on analysis of stable paths, we show that such models, when deployed naïvely for modular verification, are unsound. To rectify the situation, we adopt a routing model based around a logical notion of time and develop a sound, expressive, and scalable verification engine. Our system requires that a user specifies interfaces between module components. We develop methods for defining these interfaces using predicates inspired by temporal logic, and show how to use those interfaces to verify a range of network-wide properties such as reachability or access control. Verifying a prefix-filtering policy using a non-modular verification engine times out on an 80-node fattree network after 2 hours. However, Timepiece verifies a 2,000-node fattree in 2.37 minutes on a 96-core virtual machine. Modular verification of individual routers is embarrassingly parallel and completes in seconds, which allows verification to scale beyond non-modular engines, while still allowing the full power of SMT-based symbolic reasoning.
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This content will become publicly available on September 1, 2026
Analyzing Action Interference of Administrative Obligations for SMT-Based Verification
Obligations in the Next-Generation Access Control (NGAC) standard enable the development of security-intensive workflow systems where access privileges evolve over time. However, specifying obligations for dynamic access requirements poses challenges, with errors having the potential to cause significant harm to the authorization state in NGAC applications. To identify and rectify such errors, our work aims to verify obligations by translating NGAC policies into logical formulas in SMTs (Satisfiability Modulo Theories). A primary challenge lies in the formalization of procedural obligations into declarative SMT formulas, given the potential for interference among administrative actions within an obligation. To address this issue, this paper analyzes all conflicts among obligation actions and formalizes them as logical formulas for the correct SMT-based verification of obligations in NGAC policies. We implemented the approach using the cvc5 solver and applied it to real-world systems. The results illustrate the successful formalization and verification of access control requirements.
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- Award ID(s):
- 2318891
- PAR ID:
- 10657576
- Publisher / Repository:
- MDPI
- Date Published:
- Journal Name:
- Journal of Cybersecurity and Privacy
- Volume:
- 5
- Issue:
- 3
- ISSN:
- 2624-800X
- Page Range / eLocation ID:
- 66
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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