abstract = "Password cracking is the term commonly used to
describe the illegal action of gaining access to clear
text versions of user passwords. Hackers are notorious
for stealing encrypted passwords and cracking them. The
same action of password cracking can be used by system
administrators to protect their systems from weak user
passwords. By applying a password cracker to user
passwords, weak or easy to crack passwords can be
identified. Through the design of a password cracker
system administrators can prevent weak passwords from
being saved onto their systems. Users can also be made
aware of the strength of the passwords they are
currently employing. A manner in which password
cracking can be made more effective is to produce a few
guess words with a high probability of cracking a large
number of passwords. Research has revealed the
successful use of grammars to generate effective
password guess words. In order to generate password
grammars, genetic programming is applied to grammar
induction for the purpose of inducing grammars that
will be used as input to a password cracking tool. To
achieve this goal the current paper looks at the
performance of genetic programming in the induction of
regular and context-free languages. The results of the
experiments conducted are promising, with the genetic
programming algorithm managing to induce twenty three
of the twenty six context-free languages it was tested
on. The value of this paper lies in the evaluation of
the genetic programming technique for grammar
induction. The output of the research will be used to
build a genetic programming system which can evolve
grammars to generate password guess words to crack user
created passwords.",
notes = "page 181 'For the context-free languages, the GP
algorithm managed to evolve grammars for ten out of the
eleven
languages.'