Intrusion Countermeasures Electronics (ICE) is a term used in the cyberpunk subgenre to refer to security programs which protect computerized data from being accessed by hackers.
[1] When viewed in a cyberspace virtual reality environment, these constructs are often represented by actual walls of ice, stone, or metal.
Though real-life firewalls, anti-virus software and similar programs fall under this classification, the term has little real world significance and remains primarily a science fiction concept.
[3] "The Gibsonian concept of cyberspace [...] fed back into both computer and information systems design and theory," wrote Roger Burrows.
[4] The term ICE has occasionally been used for real-world software: On April 28, 2009, the Information and Communications Enhancement Act, or ICE Act for short, was introduced to the United States Senate by Senator Tom Carper to make changes to the handling of information security by the federal government, including the establishment of the National Office for Cyberspace.