Automatic Methods for Analyzing Non-Repudiation Protocols with an Active Intruder

TL;DR

This paper introduces a new, general method for analyzing non-repudiation protocols by modeling participant knowledge, implemented in the AVISPA Tool, which successfully identified previously unknown attacks on a specific protocol.

Contribution

It presents a novel, easy-to-implement approach for verifying non-repudiation protocols by extending existing tools to handle participant knowledge.

Findings

Discovered two unknown attacks on the Cederquist-Corin-Dashti protocol.

Extended AVISPA Tool to analyze non-repudiation properties.

Method is simple to integrate and applicable to various protocols.

Abstract

Non-repudiation protocols have an important role in many areas where secured transactions with proofs of participation are necessary. Formal methods are clever and without error, therefore using them for verifying such protocols is crucial. In this purpose, we show how to partially represent non-repudiation as a combination of authentications on the Fair Zhou-Gollmann protocol. After discussing its limits, we define a new method based on the handling of the knowledge of protocol participants. This method is very general and is of natural use, as it consists in adding simple annotations, like for authentication problems. The method is very easy to implement in tools able to handle participants knowledge. We have implemented it in the AVISPA Tool and analyzed the optimistic Cederquist-Corin- Dashti protocol, discovering two unknown attacks. This extension of the AVISPA Tool for handling non-repudiation opens a highway to the specification of many other properties, without any more change in the tool itself.