anchor.diff:  (defvar *des-public-keys* nil
     "List of public keys for each client that may talk to the server.")
   
  -(defstruct des-key
  -  fullname key)
  +(defstruct des-key fullname key)
   
   (defun add-des-public-key (fullname key)
     (push (make-des-key :fullname fullname
  
positive.code: 
  (defxstruct authdes-fullname ()
    (name :string)
    (key (:varray* :octet)) ;; encrypted conversion key
    (window (:array :octet 4)))
  
  (defxunion authdes-cred (authdes-namekind)
    (:adn-fullname authdes-fullname)
  
negative.code:   (cyclic-find-if (lambda (c)
  		    (= (des-context-nickname c) nickname))
  		  *des-contexts*))
  
  