Tripathi, AnandAhmed, Tanvir2020-09-022020-09-022001-11-20https://hdl.handle.net/11299/215489The focus of this paper is on building secure distributed collaboration and workflow systems from their high level specifications. We identify here unique requirements of role based security in dynamic collaboration environments, specifically role admission and activation constraints, separation of duties, a model for multi-user participation in a role, and intra and inter role coordination. We present a role-based model for specifying coordination and security requirements in collaboration systems. It also supports hierarchical structuring of a large collaboration environment using nested activities, which can be created dynamically. An activity defines a naming scope and a protection domain to specify security and coordination policies. We describe here how a middleware is used to realize and support a collaboration environment from its specifications, implementing the required security and coordination policies.en-USReport