The Free On-line Dictionary of Computing (30 December 2018):

Intrusion Countermeasure Electronics

    (ICE) A contrived acronym for security
   software, coined by Usenetter Tom Maddox and popularised by
   William Gibson's cyberpunk SF novels.  In Gibson's novels
   ICE software responds to intrusion by attempting to literally
   kill the intruder.

   The term is not in serious use as of 2000 apart from the
   commercial software product, BlackICE and a growing number
   of others.

   See also: icebreaker.

   [Jargon File]

   (2000-03-18)