Hash sources
============

The default source for plone.session is the hash source:

  >>> session = self.folder.pas.session
  >>> source = session.source
  >>> source
  <plone.session.sources.hash.HashSession object at ...>


The secret ring
===============

The hash plugin uses a ring of secrets, where the last generated secret is
used to sign secrets.

Since a single signing secret is used we should get the same secret if we
generate an identifier multiple times:

  >>> one = source.createIdentifier("john.doe")
  >>> two = source.createIdentifier("john.doe")
  >>> one == two
  True
