Trust and security through message level enforcement

Achieving security on the Grid must rely on end-to-end security from reasoning at VO level (which is the topic of another section) to lower level enforcement mechanism. Especially we will consider here the benefits of message level enforcement (and more technically through the use of interceptors). Message level reasoning can provide very flexible and highly adaptive mechanisms to detect change in security parameters (eg. continuous control on resource access).
Trust between security domains is also important in grid composed of heterogeneous entities. Each entity has their security level and policy. Each entity must be trusted to ensure that the security of another one is not affected. Thrust between entities must be established to provide a secure service.