A Decentralized Approach for Controlled Sharing of Resources in Virtual Communities

A Virtual Community is a composition of heterogeneous and independently designed subsystems, focusing on large-scale resource sharing, innovative applications and in some cases high performance computation. The sharing that we refer to is the direct access to computers, software, and data emerging in fields like science, industry and engineering. Several open issues need to be addressed in order to make possible these dynamic environments, such as how to manage access policies to coordinate resource sharing, how to establish a community, how to ensure that member communities respect community policies and so on. Protocols to define how to establish sharing relationships between participants must also be enforced: each member entering in a community has to agree on what it is permitted to do and also what it is obliged to do. Resource sharing must be carefully controlled, with resource providers and controllers defining clearly and carefully what is shared, who is allowed to share and the conditions under which the sharing occurs. Resource sharing is therefore conditional, each provider has to define and publish the conditions under which it makes its resources available. Such conditions (or policies) must always be consistent with the community policies, regulating the entire organization. Furthermore, once resource sharing is defined, the members are obliged to give access to its services according to the stated rules.