Borland VisiBroker® 7.0 - Borland Technical Publications

Context PropagationFor example, a client request goes to Server 1, and Server 1 performs theauthentication of the identity of the client. However, Server 1 passes the client requestto Server 2, which may in turn pass the request to Server 3, and so forth. See thefollowing diagram:Each subsequent server (Server 2 and Server 3) can assume that the client identityhas been verified by Server 1 and thus the identity is trusted. The server that ultimatelyfulfills the client request, such as Server 3, need only perform the access controlauthorization.By default the identity is authenticated only at the first tier server and is asserted. It isthe asserted identity that propagates to other tiers.ImpersonationImpersonation is the form of identity assertion where there is no restriction on whatresources the mid-tier server can access on the end-tier server. The mid-tier servercan perform any task on behalf of the client.DelegationThe inverse of impersonation, delegation is the form of identity assertion where theclient explicitly delegates certain privileges to the server. In this case, the server isallowed to perform only certain actions as dictated by the client. VisiSecure performsonly simple delegation.20 VisiBroker Security Guide