Basic credential checkers
| Variable | ANONYMOUS | An empty tuple used to represent the anonymous avatar ID. |
| Interface | ICredentialsChecker | An object that can check sub-interfaces of ICredentials. |
| Class | AllowAnonymousAccess | A credentials checker that unconditionally grants anonymous access. |
| Class | InMemoryUsernamePasswordDatabaseDontUse | An extremely simple credentials checker. |
| Class | FilePasswordDB | A file-based, text-based username/password database. |