what is DESZIP

From: Jonathan Wilson (jonwil_at_tpgi.com.au)
Date: 03/30/04 

Date: Tue, 30 Mar 2004 11:51:59 +0800

I read about this program called DESZIP in a book about hackers.
What I want to know is:
1.just what DESZIP is
2.why the hackers wanted it so much
3.why it was classified when it was first written
and 4.wht it is still classified