Crack began in 1990 when Alec Muffett, a Unix system administrator at the University of Wales Aberystwyth, was trying to improve Dan Farmer's pwc cracker in COPS.
Randal L. Schwartz, a notable Perl programming expert, in 1995 was prosecuted for using Crack[8][9] on the password file of a system at Intel, a case the verdict of which was eventually expunged.
These could range from the simple (do not change) to the extremely complex - the documentation gives this as an example: These rules could also process the GECOS field in the password file, allowing the program to use the stored names of the users in addition to the existing word lists.
Crack's dictionary generation rule syntax was subsequently borrowed[12] and extended[13] by Solar Designer for John the Ripper.
The dictionary generation software for Crack was subsequently reused by Muffett[14] to create CrackLib, a proactive password checking library that is bundled with Debian[15] and Red Hat Enterprise Linux-derived[16] Linux distributions.