jQuery Password Entropy
This jQuery plug-in is built to give an estimate of the entropy of a password. Initial calculations assume a randomly generated password is used, and then applies a heuristics approach to penalize some common problems that arise with human-generated passwords.
Some of the patterns used for creating the estimates are based on data collected in the paper "Testing Metrics for Password Creation Policies by Attacking Large Sets of Revealed Passwords" by Weir et. al. and can be recommended as further reading for those interested.
The default blacklisted passwords are based on lists downloaded from http://www.skullsecurity.org/ and then compiled to match the purpose of this plug-in. Only passwords with eight characters or more were kept in the list to save space, since my password policy doesn't allow anything shorter anyway.
Created by Erik Brännström.
Options
- display : Selector for the element to display strength.
- functions : Array of functions that receive the current entropy and password. Must return a value that will replace the current value. Options are merged with defaults.
- strings : Array with six elements, setting the result string.
- classes : Array with six elements, setting the class of the display element based on the strength.
- blacklist : Array containing blacklisted words that should not be used as passwords. Options are merged with defaults.
Example
$('input[type=password]').passwordEntropy({ 'display' : 'div.result' });
License
Copyright (C) 2011 by Erik Brännström
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.