Gibson's cyberpunk SF novels: a contrived acronym for `Intrusion Countermeasure Electronics'] Security software (in Gibson's novels, software that responds to intrusion by attempting to literally kill the intruder). Also, `icebreaker': a program designed for cracking security on a system.Neither term is in serious use yet as of mid-1993, but many hackers find the metaphor attractive, and each may develop a denotation in the future. In the meantime, the speculative usage could be confused with `ICE', an acronym for "in-circuit emulator".