Virtual Organization (VO) is a collection of users and distributed resources, in which resources are shared by users. Creating VOs is very important task in Grid computing. VOs are dynamically created for some goals and then disappear after the goals are achieved. Conventional authorization architectures for the Grid have been proposed in a single VO environment. However, in reality we often need to handle the situation of several dynamically created VOs. Hence, enough fine-grained authorization methods for all the Grid entities such as resource providers, VO manger, and users do not exist under the dynamic VO environment. In this paper, we propose a TAS architecture to support a fine-grained authorization service in a dynamic VO environment. In contrast to the conventional architecture, TAS architecture uses a ticket that is unforgeable and exchangeable among VO entities for resource control. Categories and Subject Descriptors D.4.6 [Operation Systems]: Security and Protection – ac...