Methodology and design alternatives for trust services in xtreemOS

This deliverable aims at providing a complete description of the techniques for trust management in XtreemOS. Our presentation of trust revolves around three main elements: the model of trust adopted in XtreemOS, the mechanisms of exchanging such trust and finally, trust-enhancement services. The XtreemOS trust model gives a high-level overview of how the different organisations, users, resources and services are divided and managed in XtreemOS. The deliverable presents the main elements of the XtreemOS trust model: domains, certification authorities, credentials and trust protocols. It is also discussed possible alternative settings for the trust model, including the pros and cons of each setting. The main trust-establishment mechanism in XtreemOS is credentials. By using credentials, such as digital certificates, an entity can convey certain attributes about itself to other entities for the purpose of enhancing the trustworthiness of the former. The deliverable describes the type of information carried in XtreemOS certificates and the main mechanisms for credential distribution. Trust services permit the users of the XtreemOS operating system to have better faith in its dependability when handling their job submissions. Our main example of such services is the isolation mechanism, which allows users to run their jobs in different degrees of isolation from other jobs.