These functions allow you to use the CrackLib library to test the 'strength' of a password. In order to use these functions, you must compile PHP with Crack support by using the --with-crack option.
More information regarding CrackLib along with the library can be found at http://www.users.dircon.co.uk/~crypto/.
Cracklib is useful in testing the 'strength' of a password that checks length, use of upper and lower case and a check against the specified CrackLib dictionary. CrackLib will also give helpful diagnostic messages that will help 'strengthen' the password.
This example shows how to open a CrackLib dictionary, test a given password, retrieve any diagnostic messages, and close the dictionary.
Example 1. CrackLib example