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Posted 20 Sep 2007

Contacting a Registration Server to obtain a unique registration key based on unique machine ID

, 20 Sep 2007
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This article describes usage of System.Net.WebRequest & WebResponse to contact a Server and obtain a registration key for a Windows application.
Screenshot - registration.jpg


Sometimes in the industry, it is required to collect some unique machine information and send it to a server for the purpose of creating a unique registration key based on the hardware information. This is required in the case when the software requires a per PC registration. Thus we can collect the machine information of the PC in which the software was installed, and issue a registration key which will be valid only for that machine.


Using WMI functionality, it is possible to collect machine specific hardware information.
In .NET, one can use System.Management.ManagementClass for this purpose. (This is explained in this article.)

The problem arises when we try to send this information to the server. Because of the firewall that is present in OSes starting from WinXP, if we try to send data from our application to an external server, the firewall pops up a warning to the user informing her/him that the application is trying to send data and asks the user whether she/he wants to proceed or block the application. (Also this approach will fail if the local network is connected to the Internet through a firewall, which is configured to block anything other than HTTP traffic.)

The solution thus comes in the form of HTTP (i.e. we have to send the data through HTTP).
In .NET, this is easily achieved through System.Net.WebRequest or by using a Web Service. This article uses the WebRequest approach.

Using the Code

In the class ContactRegistationServer (UserRegistration project), you will notice that we are creating a WebRequest and passing the hardware information through QueryString.

WebResponse registrationKey = null;
String url_string = "http://localhost/Registration/Registration.aspx"
    + "?CPU=" + System.Web.HttpUtility.UrlEncode(hardwareInfo.cpuID)
    + "&BIOS=" + System.Web.HttpUtility.UrlEncode(hardwareInfo.biosID)
    + "&MB=" + System.Web.HttpUtility.UrlEncode(hardwareInfo.baseID)
    + "&DISK=" + System.Web.HttpUtility.UrlEncode(hardwareInfo.diskID)
    + "&MAC=" + System.Web.HttpUtility.UrlEncode(hardwareInfo.macID)
    + "&VIDEO=" + System.Web.HttpUtility.UrlEncode(hardwareInfo.videoID);
    WebRequest requestRegistration = WebRequest.Create(url_string);
    registrationKey = requestRegistration.GetResponse();
catch (Exception ex)
    System.Windows.Forms.MessageBox.Show("Failed connecting to server");

On the server (Refer project 'TestPage' Registration.aspx.cs), the QueryString received from the client is retrieved and a unique registration key is produced and returned to the user.

//Call the Foolproof Registration Key algorithm :)
TheFoolProofRegistrationKey regKey = new TheFoolProofRegistrationKey();
String key = regKey.getRegistrationKey(Request.QueryString["CPU"]);

Notes: If You Decide to Download and Run the Program

If you decide to download and try the application, please make sure to create a virtual folder of the name "Registration" on your local Web server. This is required as the WebRequest is using the following URL: http://localhost/Registration/Registration.aspx (or else copy the files to a folder by the name Registration under the server root folder).

Just for the use of a novice, I have attached a few screen shots on how to add the virtual directory on IIS.

Screenshot - virtual3.jpg

And finally you should have something as follows:

Screenshot - virtual2.jpg

Points of Interest

For testing purposes, I also tried to connect to the server from a different PC: (e.g.: and it still worked - the firewall did not complain:).
I did not try to connect to a server outside our network, but I guess that should also work...

To collect machine specific information, use the code in this article.


  • 20th September, 2007: Initial post


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


About the Author

Sajjitha Gunawardana
Web Developer
Sri Lanka Sri Lanka
coding in C# C++ C


Code in English, not Gibberish Smile | :)

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Comments and Discussions

QuestionD we need any Crypto library? Pin
Giri Ganji24-Sep-07 19:33
memberGiri Ganji24-Sep-07 19:33 
AnswerRe: D we need any Crypto library? Pin
Sajjitha Gunawardana25-Sep-07 5:07
memberSajjitha Gunawardana25-Sep-07 5:07 
GeneralOne Caveat Pin
TrendyTim24-Sep-07 12:56
memberTrendyTim24-Sep-07 12:56 
GeneralGood Article Pin
merlin98121-Sep-07 4:17
membermerlin98121-Sep-07 4:17 
GeneralRe: Good Article Pin
Sajjitha Gunawardana21-Sep-07 5:26
memberSajjitha Gunawardana21-Sep-07 5:26 
GeneralRe: Good Article Pin
merlin98121-Sep-07 7:45
membermerlin98121-Sep-07 7:45 
GeneralRe: Good Article Pin
MathiasW24-Sep-07 12:47
memberMathiasW24-Sep-07 12:47 

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