Package cracklib

A password-checking library

CrackLib tests passwords to determine whether they match certain
security-oriented characteristics, with the purpose of stopping users
from choosing passwords that are easy to guess. CrackLib performs
several tests on passwords: it tries to generate words from a username
and gecos entry and checks those words against the password; it checks
for simplistic patterns in passwords; and it checks for the password
in a dictionary.

CrackLib is actually a library containing a particular C function
which is used to check the password, as well as other C
functions. CrackLib is not a replacement for a passwd program; it must
be used in conjunction with an existing passwd program.

Install the cracklib package if you need a program to check users'
passwords to see if they are at least minimally secure. If you install
CrackLib, you will also want to install the cracklib-dicts package.

System Administration (Section 8)
cracklib-check takes a list of passwords from stdin and checks them via libcrack2's FascistCheck(3) sub routine.
cracklib-format takes a list of text files each containing a list of words, one per line, It lowercases all words, removes control characters, and sorts the...
create-cracklib-dict takes one or more word list files as arguments and converts them into cracklib dictionaries for use by password checking programs. The...
update-cracklib builds a compressed and accumulated version of wordlists stored in the directories given in cracklib's configuration file...