Paper 2018/766

Noise Explorer: Fully Automated Modeling and Verification for Arbitrary Noise Protocols

Nadim Kobeissi and Karthikeyan Bhargavan

Abstract

The Noise Protocol Framework, introduced recently, allows for the design and construction of secure channel protocols by describing them through a simple, restricted language from which complex key derivation and local state transitions are automatically inferred. Noise "Handshake Patterns" can support mutual authentication, forward secrecy, zero round-trip encryption, identity hiding and other advanced features. Since the framework's release, Noise-based protocols have been adopted by WhatsApp, WireGuard and other high-profile applications. We present Noise Explorer, an online engine for designing, reasoning about and formally verifying arbitrary Noise Handshake Patterns. Based on our formal treatment of the Noise Protocol Framework, Noise Explorer can validate any Noise Handshake Pattern and then translate it into a model ready for automated verification. We use Noise Explorer to analyze 50 Noise Handshake Patterns. We confirm the stated security goals for 12 fundamental patterns and provide precise properties for the rest. We also analyze unsafe Noise patterns and discover potential attacks. All of this work is consolidated into a usable online tool that presents a compendium of results and can parse formal verification results to generate detailed-but-pedagogical reports regarding the exact security guarantees of each message of a Noise Handshake Pattern with respect to each party, under an active attacker and including malicious principals. Noise Explorer evolves alongside the standard Noise Protocol Framework, having already contributed new security goal verification results and stronger definitions for pattern validation and security parameters.