Formal Reasoning About Trusted Third Party Protocols

Aaron Hunter

2025

Abstract

A trusted third party (TTP) is an entity that facilitates communication between agents by acting as an intermediary. Typical roles for a trusted third party include the establishment of session keys or the validation of commitment schemes. In a formal setting, this requires a model that provides some mechanism for representing trust and reasoning about dynamic beliefs. In this paper, we demonstrate how this can be captured using a combined modal logic of trust and belief. Our formalism uses plausibility models and model transformations to capture belief revision in a protocol run. It is novel in that it uses the modal accessibility relations in the logic to define a notion of trust, without requiring any additional formal machinery. We define the formal semantics of the logic, sketch the axiomatization, and demonstrate the basic verification methodology. Challenges are discussed, as well as issues related to practical deployment.

Paper Citation

in Harvard Style

Hunter A. (2025). Formal Reasoning About Trusted Third Party Protocols. In Proceedings of the 17th International Conference on Agents and Artificial Intelligence - Volume 3: ICAART; ISBN 978-989-758-737-5, SciTePress, pages 926-932. DOI: 10.5220/0013237600003890

in Bibtex Style

@conference{icaart25,
author={Aaron Hunter},
title={Formal Reasoning About Trusted Third Party Protocols},
booktitle={Proceedings of the 17th International Conference on Agents and Artificial Intelligence - Volume 3: ICAART},
year={2025},
pages={926-932},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0013237600003890},
isbn={978-989-758-737-5},
}

in EndNote Style

TY - CONF

JO - Proceedings of the 17th International Conference on Agents and Artificial Intelligence - Volume 3: ICAART
TI - Formal Reasoning About Trusted Third Party Protocols
SN - 978-989-758-737-5
AU - Hunter A.
PY - 2025
SP - 926
EP - 932
DO - 10.5220/0013237600003890
PB - SciTePress