[Zope] acl_users and encrypted passwords

When you encrypt your passwords in an acl_users User Folder, is there a way to check that the old password is correct? I'm building an app that allows the user to change her password with the usual form of: Old: ________ New: ________ Confirm: ________ -- Peter Bengtsson, work www.fry-it.com home www.peterbe.com hobby www.issuetrackerproduct.com fun crosstips.org