Client Impersonation (Authorization)

Impersonation is the ability of a thread to execute using different security information than the process that owns the thread. Typically, a thread in a server application impersonates a client. This allows the server thread to act on behalf of that client to access objects on the server or validate access to the client's own objects.

The Microsoft Windows API provides the following functions to begin an impersonation:

For most of these impersonations, the impersonating thread can revert to its own security context by calling the RevertToSelf function. The exception is the RPC impersonation, in which the RPC server application calls RpcRevertToSelf or RpcRevertToSelfEx to revert to its own security context.