Formal Logic for Reasoning about Contextual Trust in Self-Authenticating Traditional Addresses (SATAs)

Core Concepts

A formal logic is introduced to reason about contextual trust in the binding of identities (domain names and onion addresses) and their associated descriptive properties (labels) in the context of Self-Authenticating Traditional Addresses (SATAs).

Abstract

The paper introduces a formal logic for reasoning about contextual trust in web addresses, particularly Self-Authenticating Traditional Addresses (SATAs). SATAs combine the meaningfulness of traditional domain names with the self-authentication of onion addresses.
The logic allows reasoning about:

The binding of a domain name and onion address into a single identity (a "bound" SATA)
Descriptive properties (labels) associated with a bound SATA, such as it being a news site, belonging to a government, or relating to a specific topic
Delegation of trust with respect to these labels, including more specific or more generic labels
The interaction between the binding of identity and the binding of labels
Key aspects of the logic include:

A partial order on labels that captures more specific or more generic relationships
Axioms that describe when a principal can trust the binding of an identity or the assertion of a label by a SATA
Local axiom schemata that allow principals to express their own trust assumptions about labels or SATAs
Soundness and completeness results for the logic
The logic provides a formal foundation for reasoning about the contextual trust properties of SATAs, which complement the structural trust established via domain name registration and TLS certificates.

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Key Insights Distilled From

A Logic of Sattestation

by Aaron D. Jag... at arxiv.org 05-06-2024

https://arxiv.org/pdf/2405.01809.pdf

Deeper Inquiries

Question 1

To extend this logic to reason about the evolution of trust over time as domain ownership, keys, or labels change, we would need to introduce a temporal element into the framework. This could involve adding a time parameter to the worlds in the model, allowing for the representation of changes over time. Each world would then correspond to a specific point in time, and the accessibility relation between worlds would capture how trust relationships evolve over time. The assignment function would need to account for changes in domain ownership, keys, or labels by updating the information associated with each world as these changes occur. Additionally, new axioms or rules could be introduced to formalize how trust in identities and assertions may change over time based on these alterations.

Question 2

Relying on contextual trust properties, as described in the logic of Sattestation, has certain limitations compared to more structural trust mechanisms like X.509 certificates. One potential limitation is the reliance on subjective contextual information, which may introduce ambiguity and variability in trust decisions. Contextual trust is based on descriptive properties and associations, which can be more prone to manipulation or misinterpretation compared to the strict hierarchical structure of X.509 certificates. Additionally, contextual trust may require more complex reasoning and inference mechanisms to establish and maintain trust relationships, leading to potential challenges in implementation and verification. Structural trust mechanisms like X.509 certificates provide a standardized and widely accepted framework for authentication, offering a more straightforward and universally understood approach to trust establishment.

Question 3

This logic could be applied to analyze the security properties and trust guarantees provided by real-world SATA deployments by evaluating the trust relationships and assertions made by SATAs in different scenarios. By using the formal language and axiomatic logic introduced in the context, one could assess the soundness and completeness of trust statements derived from initial assumptions in a real-world SATA deployment. The logic could be used to reason about delegation of trust, relationships between labels, and the overall trustworthiness of SATAs in various contexts. By applying the rules and axioms to specific cases of SATA deployments, one could analyze the effectiveness of contextual trust roots in providing resistance to vulnerabilities and ensuring the integrity of web connections. This analysis could help identify potential security risks, validate trust assumptions, and enhance the overall security posture of SATA-based systems.