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Google Password Strength API

By , 9 Nov 2007
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Screenshot - GooglePasswordStrength.gif

Introduction

Do you have an iGoogle Account? Well, if you are like the rest of the world that use the Internet, you will have, which also means that you have seen the very cool (and useful) "Password strength" control.

This control has a very intelligent API to determine if the password you entered is any good. It is "intelligent" in the fact that it does not just check that you have a password that is larger than six characters; e.g., a password "aaaaaaaaaaaa" will come out as "Weak", "my password" as "Good", and "grty3657DF?£hr4" as (yes you guessed it!) "Strong".

The big secret is this is actually a public API from Google, to which you can pass a password and it will return the password strength from 1 (least secure) to 4 (most secure). You can view it here.

And here is the "but", there is no interface for the control and it is not openly advertised by Google.

Background

When I found a use for such a control on a website I'm currently building, I first looked at the Microsoft AJAX Toolkit. At first, this worked great; however, I felt that the algorithm used was not as strong as the Google one, and I kept on getting JavaScript errors due to that control.

Bring on this control.

Using the code

The easiest way is to add a reference to the GooglePasswordStrength.dll, then add a section into the web.config:

<pages> 
    <controls> 
        <add tagPrefix="google" namespace="GooglePasswordStrength" 
             assembly="GooglePasswordStrength"/> 
    </controls> 
</pages>

Then, add the control to your page, and attach it to an asp:TextBox.

<table> 
    <tr> 
        <td><asp:TextBox ID="txtPassword" runat="server" /></td>
        <td><google:PasswordStrength ID="PS" 
                TargetControlID="txtPassword" 
                CssClass="password" runat="server" /></td>
    </tr> 
</table>

Points of interest

The control utilises AJAX, but does not require any third party AJAX library. However, if your application uses the Microsoft AJAX Library, the control invokes a Client Script Proxy that was written by Rick Strahl to handle all the client scripts.

Known issues

The XMLHttpRequest makes a call to the Google Password Strength API directly, so some browser settings may cause a "Permission Denied" error. This is because the XMLHttpRequest is making a call to a page outside of the local domain. In Microsoft Internet Explorer, you can change this setting under the Security Custom Level settings. Look for "Miscellaneous -> Access data sources across domains".

For a more robust, permanent solution, you will need to change the call to a page on the same domain and make a WebRequest to the Google API from there.

Update

  1. In the GooglePasswordStrength.Web Project, create a new WebForm called GetPassword.aspx.
  2. In GetPassword.aspx, delete all the lines except the @Page directive line.
  3. Open GetPassword.aspx.cs.
  4. In the Page_Load method, add the following code:
  5. string passwd = Request.QueryString["Passwd"];
    
    string GUrl = string.Format("https://www.google.com/" + 
                  "accounts/RatePassword?Passwd={0}", passwd);
    
    WebRequest webRequest = WebRequest.Create(GUrl);
    WebResponse webResponse = webRequest.GetResponse();
    StreamReader reader = new StreamReader(webResponse.GetResponseStream());
    
    Response.Clear();
    Response.Output.Write(reader.ReadToEnd());
    Response.End();
  6. Open PasswordStrength.js.
  7. On line 76, there is the xmlHttpObj.open method. Replace "https://www.google.com/accounts/RatePassword?Passwd=" with "GetPassword.aspx?Passwd=".
  8. Also, in the PasswordStrength.js file, replace all instances of "innerText" with "innerHTML" (I later found out that innerText is IE only).

Now, the XmlHttpRequestObject will make a call to a file on the same domain, and you will no longer get the security error.

History

  • November 2007 - Added a second demo, which uses the updated code above.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

About the Author

Roger Chapman
Software Developer (Senior) Storm ID Ltd.
United Kingdom United Kingdom
No Biography provided

Comments and Discussions

 
Generalfacing a problem in running ur demo.. PinmemberJai P30-Nov-10 18:47 
QuestionDoes PasswordStrength Control have Multilingual support ? PinmemberThy.Maverick18-Nov-09 18:08 
GeneralProblem when the control is invisible on page load Pinmemberdc9917-Apr-09 1:40 
GeneralProblem using Login and CreateUserWizard controls PinmemberMember 125823623-Jan-09 4:45 
QuestionOk, I am doing some things incorrectly obvioulsy... Pinmembertopdog5018-Jul-08 10:31 
AnswerRe: Ok, I am doing some things incorrectly obvioulsy... PinmemberRoger Chapman20-Jul-08 22:27 
QuestionChecking the strength Pinmemberwes lowe19-Jun-08 3:55 
AnswerRe: Checking the strength PinmemberRoger Chapman19-Jun-08 4:05 
QuestionRe: Checking the strength Pinmemberwes lowe19-Jun-08 4:42 
AnswerRe: Checking the strength PinmemberRoger Chapman19-Jun-08 4:55 
GeneralRe: Checking the strength Pinmemberwes lowe19-Jun-08 5:26 
GeneralHave a bug.. Pinmemberrodrigosor10-Jun-08 16:33 
AnswerRe: Have a bug.. PinmemberRoger Chapman10-Jun-08 22:13 
GeneralGoogle Password Strength API - demo2 not working PinmemberLeelavathy22-May-08 5:14 
AnswerRe: Google Password Strength API - demo2 not working PinmemberRoger Chapman22-May-08 5:25 
GeneralRe: Google Password Strength API - demo2 not working PinmemberLeelavathy23-May-08 4:49 
AnswerRe: Google Password Strength API - demo2 not working PinmemberRoger Chapman23-May-08 6:26 
Questioni could not run your control PinmemberEhsan Golkar28-Sep-07 2:20 
AnswerRe: i could not run your control PinmemberRoger Chapman28-Sep-07 2:26 
GeneralRe: i could not run your control PinmemberEhsan Golkar28-Sep-07 9:55 
GeneralRe: i could not run your control PinmemberRoger Chapman30-Sep-07 23:10 
AnswerRe: i could not run your control PinmemberEhsan Golkar1-Oct-07 19:40 
AnswerRe: i could not run your control PinmemberRoger Chapman1-Oct-07 22:36 
Generali m having problem Pinmembergoodonebond8-Aug-07 21:25 
AnswerRe: i m having problem PinmemberRoger Chapman8-Aug-07 22:10 
GeneralThere's a better one in the Microsoft AJAX toolkit Pinmemberreach4thelasers19-Jun-07 1:16 
AnswerRe: There's a better one in the Microsoft AJAX toolkit PinmemberRoger Chapman19-Jun-07 1:34 
AnswerRe: There's a better one in the Microsoft AJAX toolkit PinmemberRoger Chapman19-Jun-07 1:38 
GeneralRe: There's a better one in the Microsoft AJAX toolkit PinmemberNapp3-Sep-07 14:44 
NewsRe: There's a better one in the Microsoft AJAX toolkit PinmemberRoger Chapman30-Sep-07 23:15 
GeneralPrivacy issue PinmemberJulien Couvreur18-Jun-07 19:07 
GeneralRe: Privacy issue PinmemberKevin Jensen19-Jun-07 11:15 
AnswerRe: Privacy issue [modified] PinmemberRoger Chapman19-Jun-07 22:14 
GeneralRe: Privacy issue PinmemberSecrets25-Jun-07 19:53 
GeneralRe: Privacy issue PinmemberJeffrey Walton26-Jun-07 13:48 
AnswerRe: Privacy issue Pinmembergreendaale9-Nov-07 2:41 
GeneralGood Idea Pinmembermerlin98118-Jun-07 11:50 
AnswerRe: Good Idea Pinmembervistaapi18-Jun-07 16:14 

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Article Copyright 2007 by Roger Chapman
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