Design and implementation of extensible middleware for non-repudiable interactions

Abstract

Non-repudiation is an aspect of security that is concerned with the creation of irrefutable audits of an interaction. Ensuring the audit is irrefutable and verifiable by a third party is not a trivial task. A lot of supporting infrastructure is required which adds large expense to the interaction. This infrastructure comprises, (i) a non-repudiation aware run-time environment, (ii) several purpose built trusted services and (iii) an appropriate non-repudiation protocol. This thesis presents design and implementation of such an infrastructure. The runtime environment makes use of several trusted services to achieve external verification of the audit trail. Non-repudiation is achieved by executing fair non-repudiation protocols. The Fairness property of the non-repudiation protocol allows a participant to protect their own interests by preventing any party from gaining an advantage by misbehaviour. The infrastructure has two novel aspects; extensibility and support for automated implementation of protocols. Extensibility is achieved by implementing the infrastructure in middleware and by presenting a large variety of non-repudiable business interaction patterns to the application (a non-repudiable interaction pattern is a higher level protocol composed from one or more non-repudiation protocols). The middleware is highly configurable allowing new non-repudiation protocols and interaction patterns to be easily added, without disrupting the application. This thesis presents a rigorous mechanism for automated implementation of non-repudiation protocols. This ensures that the protocol being executed is that which was intended and verified by the protocol designer. A family of non-repudiation protocols are taken and inspected. This inspection allows a set of generic finite state machines to be produced. These finite state machines can be used to maintain protocol state and manage the sending and receiving of appropriate protocol messages. A concrete implementation of the run-time environment and the protocol generation techniques is presented. This implementation is based on industry supported Web service standards and services.