Distributed Role-Based Access Control (dRBAC) is a scalable, decentralized trust-management and access-control mechanism for systems that span multiple administrative domains. dRBAC represents controlled actions in terms of roles, which are defined within the trust domain of one entity and can be transitively delegated to other roles within a different trust domain. dRBAC utilizes PKI to identify all entities engaged in trust-sensitive operations and to validate delegation certificates. The mapping of roles to authorized name spaces obviates the need to identify additional policy roots. dRBAC distinguishes itself from previous trust management and role-based access control approaches in its support for three features: (1) third-party delegations, which improve expressiveness by allowing an entity to delegate roles outside its namespace when authorized by an explicit delegation of assignment; (2) valued attributes, which modulate transferred access rights via mechanisms that assign and manipulate numerical values associated with roles; and (3) credential subscriptions, which enable continuous monitoring of established trust relationships using a pub/sub infrastructure to track the status of revocable credentials. This paper describes the dRBAC model, its scalable implementation using a graph-based model of credential discovery and validation, and its application in a larger security context.

Software development in distributed computation is complicated by the extra overhead of communication between connected, dispersed hosts in dynamically changing, multiple administrative domains. Many disparate technologies exist for trust management, authentication, secure communication channels, and service discovery, but composing all of these elements into a single system can outweigh principal development efforts.The NYU Disco Switchboard consolidates these connectivity issues into a single convenient, extensible architecture, providing an abstraction for managing secure, host-pair communication with connection monitoring facilities. Switchboard extends the secure authenticated communication channel abstraction provided by standard interfaces such as SSL/TLS with mechanisms to support trust management, key sharing, service discovery, and connection liveness and monitoring.We present an extensible architecture which is particularly useful in dynamically changing, distributed coalition environments. Applications that utilize Switchboard benefit from the availability of authentication, trust management, cryptography, and discovery, while retaining the simplicity of a common interface.

The growing popularity of network-based services and peer-to-peer networks has resulted in situations where components of a distributed application often need to execute in environments that are only partly trusted by the application's owner.Such deployment into partial or unstable trust environments exacerbates the classical problems of distributing decomposable services: authentication and access control, trust management, secure communication, code distribution and installation, and process rights management. Unfortunately, the application developer's burden of coping with these latter issues often dominates the benefits of service distribution.The DisCo infrastructure is specifically targeted to the development of systems and services deployed into coalition environments: networks of users and hosts administered by multiple authorities with changing trust relationships.The DisCo infrastructure provides application-neutral support for the classical problems of distributed services, thereby relieving the developer of the burden of independently managing these features. DisCo also includes support for continuously monitoring established connections, enabling corrective action from an application to cope with changing trust relationships.Our experience with building a secure video distribution service using the DisCo toolkit indicates that the latter permits distributed secure deployment into a partly trusted environment with minimal application developer effort, affording the advantages of natural expression and convenient deployment without compromising on efficiency.

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