The original "Instant Message" system libraries with Kerberos V

 This version of the library uses Kerberos V for message authentication.
 .
 This is the Project Athena Zephyr notification system.
 Zephyr allows users to send messages to other users or to groups of
 users. Users can view incoming Zephyr messages as windowgrams
 (transient X windows) or as text on a terminal.