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Method-Level Constraints

Bob Scheifler: Now that we have collected these security constraints, the next layer of aggregation is you might say that I want different security for different methods. If I do write operations for a database, I may want to authenticate myself because it is probably going to need access control in order to do the update. But maybe I would like to remain anonymous for reads. Assuming everybody can read, I really just want it to know what queries I'm making, not who I am. So you might want to have different strengths of security for different methods. We have an interface called MethodConstraints, which is a map from method to constraints. You can express for each method that a proxy implements what constraints should be used for remote calls of that method.

The server and the client can express what constraints there should be for each method made through a proxy. On a server the constraints are specified essentially at the time the remote object is exported. The server puts a lower bound on the network security. The server defines the minimum constraints that should be on any given method of any proxy to the server. The client also sets constraints on the proxy. The client defines what constraints it wants for individual calls.