How-to Make a Product key app VB 2010

[Digital]

ive gotten some great attempts for help here VS 2010 How-To Make Product Keys ? - VBForums
but this is what i want to make

im trying to make something to protect my application a simple serial key
the only thing i can think of is if textbox1.text = ("key") then blah blah blah you get it. what i really want is something that will allow me to add and remove keys without having to mod the application, something that would check a site like www.google.com/keys.html which would have a list of keys or www.google.com/keys.txt

This way i can make keys and give out my program but at the same time i can removed leaked keys

does anyone understand what im trying to get at?
thankyou inadvance

all it would do is download a text file and then scan that text file for the key that you put in textbox1
everytime it opens it would redownload the txt file.
so if your leaked key wasn't there it wouldnt open
i appreciate all the help tho!

does anyone know how i could possibly do this?
thanks in advance

[Chad]

ive gotten some great attempts for help here VS 2010 How-To Make Product Keys ? - VBForums
but this is what i want to make


does anyone know how i could possibly do this?
thanks in advance

Me: Instead of downloading the key file, because it would be easy to view and steal the key unless you encrypted several hundred times and can decrypt it back to it's original format, that is a terrible way to do it
Me: I suggest using HTTP Wrappers and reading it off of a web site, making it more secure, in a way.
Me: you would probably still have to encrypt it some though.

[MattSmith]

Use a php script thats on a site. Submit the key to the site and have the site return if its valid or not. That way the user has nothing to do with verification and all keys are server side. Add a limited try amount and you should be fine.

[Chris]

Actually there are a few steps you would want to take;

1. Resolve the DNS server (For the website you are using,) this will prevent any loopback hacking attempts (For the most part.)
2. Set-up a key creation that is individual to the PC, have it linked to an account, and then encrypted with the timestamp as it is sent to and from the PC and the WebSite.
3. Enjoy the security.