Cracking is a chemical process in which hydrocarbon molecules, particularly those derived from petroleum refining, are broken down into smaller, economically important molecules, such as petrol, but it is also used to produce raw materials for the chemical industry.

Thermal cracking was first used in 1913, as the earliest cracking system developed. It involved distilling batches of faitly heavy has oil at approx. 500 degrees Celsius, and pressures up to 25 bar.

Catalytic cracking has been in use since the 1930s, and eliminated the use for high pressures, and produced more accurate results.

cracking n.

[very common] The act of breaking into a computer system; what a cracker does. Contrary to widespread myth, this does not usually involve some mysterious leap of hackerly brilliance, but rather persistence and the dogged repetition of a handful of fairly well-known tricks that exploit common weaknesses in the security of target systems. Accordingly, most crackers are only mediocre hackers.

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.