serial key validation in c#
<p>I completed my project in C#.Net. 
I Added a serial key in it. 
At the time of installation it asks me for the key. 
The key format is also given by me, but I don't know how to validate that key.
Please give me some way how to validate that key.
Now my key is validated by visual studio or I don't know who. How is the key's validation done?
But I want to do the validation by my own. Is it possible? And if yes, how?</p>

<p>i added the customer information dialog.
and format is given by using the serial number template.
but for validation it create the problem that visual studio's logic is so simple &amp; it is if the some of digits is / by 7 then key is valid.so i want to use  the my logic like use sha1,MD5 so where i have to do coding.
The design of the customer info dialog is not show,if it is shown then i do the coding on validate button.
But now what i have to do?</p>
