A common problem for sensitive web services is informing the client,
in a reliable fashion, when a password protected resource is no
longer valid because the user is logged out of the service. This is,
in particular, considered a potential security problem by some
sensitive services, such as online banking, when the user navigates
the client's history list, which is supposed to display the resource
as it was when it was loaded, not as it is the time the user
navigates to it.
This document presents a method for collecting such sensitive
resources into a group, called a "Cache Context", which permits the
server to invalidate all the resources belonging in the group either
by direct action, or according to some expiration policy. The
context can be configured to invalidate not just the resources, but
also specific cookies, HTTP authentication credentials and HTTP over
TLS session information.