165 | | If the environment is open, the GENI principal can simply publish the relevant credential for CTF slice admin (and general) access. Because each requester now knows the beginning of the graph, they are likely to be able to include the whole proof in their first request, removing a round trip time. |
| 165 | When faber receives the candidate graph, it can check the signatures of all the credentials and satisfy itself that the graph is well formed. (It may need to find GENI's or ACM's public key, or the slice may have included them.) Faber's only credential fits on the graph and establishes a path from faber to the '''GENI.CTFaccess''' credential. Faber adds the credential to the message and returns it to the slice. Once the slice confirms the signature, the two parties agree that faber can have access. |
| 166 | |
| 167 | The collaborative process is completely characterized by adding nodes to a graph in a simple manner. Though the policies experessed by the system are complex, the process of validating any given prinicpal posses an attribute is very simple. |
| 168 | |
| 169 | Furthermore, both the rules and attributes are stored throughout the network. The slide will be ignorant of the fairly complex rules that the UCLA principal has instituted until a principal from that university authorizes itself. Note that credentials are simply signed statements (perhaps with a validity time). So the slice can keep local rules from various domains and send larger initial graphs if it chooses to. |
| 170 | |
| 171 | If the environment is open, the GENI principal can simply publish the relevant credentials encoding its rules for CTF slice access. Because each requester now knows the beginning of the graph, they are likely to be able to include the whole proof in their first request, removing a round trip time. |