no, that is not built directly into security assist, but it can be accomplished using security assist and Universal Email:
showthread.php?p=65008
the unique ID is assigned from the users table Primary key column. You can of course store the username, and or email address column in a session variable to display that information if you like, but the unique identifier for the user should be the primary key value.
You would need to use form toolkit to add any additional server side validation to the security assist registration or login form.
