Password Strength Meter

Question

I have a situation where I would like to be able to rate a users password in the web interface to my system  so that before they hit submit they know if they have a bad password   Key Requirements    Must be able to rate the password  not just pass fail  Should disable the form if the password is below a threshhold  so the user can t submit it  Look nice     Not use jQuery - we re currently using Mochikit and Y UI in this system    I ve found many password meters written in jQuery  and things like http   www passwordmeter com  that are too verbose   Can anyone suggest a good drop in javascript password rater I can use  or give an example of how to write one

User · Accepted Answer

Here s a collection of scripts  http   webtecker com 2008 03 26 collection-of-password-strength-scripts   I think both of them rate the password and don t use jQuery    but I don t know if they have native support for disabling the form

User · Answer

Password Strength Algorithm   Password Length      5 Points  Less than 4 characters     10 Points  5 to 7 characters     25 Points  8 or more  Letters      0 Points  No letters     10 Points  Letters are all lower case     20 Points  Letters are upper case and lower case  Numbers      0 Points  No numbers     10 Points  1 number     20 Points  3 or more numbers  Characters      0 Points  No characters     10 Points  1 character     25 Points  More than 1 character  Bonus      2 Points  Letters and numbers     3 Points  Letters  numbers  and characters     5 Points  Mixed case letters  numbers  and characters  Password Text Range        gt   90  Very Secure      gt   80  Secure      gt   70  Very Strong      gt   60  Strong      gt   50  Average      gt   25  Weak      gt   0  Very Weak   Settings Toggle to true or false  if you want to change what is checked in the password  var m strUpperCase    ABCDEFGHIJKLMNOPQRSTUVWXYZ   var m strLowerCase    abcdefghijklmnopqrstuvwxyz   var m strNumber    0123456789   var m strCharacters           amp        Check password   function checkPassword strPassword           Reset combination count     var nScore   0          Password length        -- Less than 4 characters     if  strPassword length  lt  5                nScore    5               -- 5 to 7 characters     else if  strPassword length  gt  4  amp  amp  strPassword length  lt  8                nScore    10               -- 8 or more     else if  strPassword length  gt  7                nScore    25                Letters     var nUpperCount   countContain strPassword  m strUpperCase       var nLowerCount   countContain strPassword  m strLowerCase       var nLowerUpperCount   nUpperCount   nLowerCount         -- Letters are all lower case     if  nUpperCount    0  amp  amp  nLowerCount    0                  nScore    10                -- Letters are upper case and lower case     else if  nUpperCount    0  amp  amp  nLowerCount    0                  nScore    20                 Numbers     var nNumberCount   countContain strPassword  m strNumber          -- 1 number     if  nNumberCount    1                nScore    10               -- 3 or more numbers     if  nNumberCount  gt   3                nScore    20                Characters     var nCharacterCount   countContain strPassword  m strCharacters          -- 1 character     if  nCharacterCount    1                nScore    10                  -- More than 1 character     if  nCharacterCount  gt  1                nScore    25                Bonus        -- Letters and numbers     if  nNumberCount    0  amp  amp  nLowerUpperCount    0                nScore    2               -- Letters  numbers  and characters     if  nNumberCount    0  amp  amp  nLowerUpperCount    0  amp  amp  nCharacterCount    0                nScore    3               -- Mixed case letters  numbers  and characters     if  nNumberCount    0  amp  amp  nUpperCount    0  amp  amp  nLowerCount    0  amp  amp  nCharacterCount    0                nScore    5              return nScore        Runs password through check and then updates GUI    function runPassword strPassword  strFieldID            Check password     var nScore   checkPassword strPassword             Get controls         var ctlBar   document getElementById strFieldID     bar             var ctlText   document getElementById strFieldID     text            if   ctlBar     ctlText              return              Set new width         ctlBar style width    nScore 1 25 gt 100  100 nScore 1 25                Color and text        -- Very Secure       if  nScore  gt   90                var strText    Very Secure           var strColor     0ca908                -- Secure     else if  nScore  gt   80                var strText    Secure           vstrColor     7ff67c                -- Very Strong     else             if  nScore  gt   80                var strText    Very Strong           var strColor     008000                -- Strong     else if  nScore  gt   60                var strText    Strong           var strColor     006000                -- Average     else if  nScore  gt   40                var strText    Average           var strColor     e3cb00                -- Weak     else if  nScore  gt   20                var strText    Weak           var strColor     Fe3d1a                -- Very Weak     else               var strText    Very Weak           var strColor     e71a1a              if strPassword length    0            ctlBar style backgroundColor           ctlText innerHTML              else           ctlBar style backgroundColor   strColor      ctlText innerHTML    strText          Checks a string for a list of characters function countContain strPassword  strCheck            Declare variables     var nCount   0       for  i   0  i  lt  strPassword length  i                   if  strCheck indexOf strPassword charAt i    gt  -1                              nCount                           return nCount        You can customize by yourself according to your requirement

User · Answer

Update  created a js fiddle here to see it live  http   jsfiddle net HFMvX  I went through tons of google searches and didn t find anything satisfying  i like how passpack have done it so essentially reverse-engineered their approach  here we go  function scorePassword pass        var score   0      if   pass          return score          award every unique letter until 5 repetitions     var letters   new Object        for  var i 0  i lt pass length  i              letters pass i      letters pass i      0    1          score    5 0   letters pass i                  bonus points for mixing it up     var variations             digits    d  test pass           lower    a-z   test pass           upper    A-Z   test pass           nonWords    W  test pass              var variationCount   0      for  var check in variations            variationCount     variations check     true    1   0            score     variationCount - 1    10       return parseInt score      Good passwords start to score around 60 or so  here s function to translate that in words  function checkPassStrength pass        var score   scorePassword pass       if  score  gt  80          return  quot strong quot       if  score  gt  60          return  quot good quot       if  score  gt   30          return  quot weak quot        return  quot  quot      you might want to tune this a bit but i found it working for me nicely

[javascript] Password Strength Meter

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