Let’s say you have to parse some HTML, find all images or some other DOM elements make some changes/optimizations and save the result. What can you do ?
Well, i needed something like that a few days ago and after Googling for couple of hours I ran across this this great library called HtmlAgilityPack.
This is a C# class which allows you to create Web and WinForm captcha control.
The class is very configurable, so finaly you could create a Captcha that suits your needs.
You can hold the Captcha secret key as a session or an encrypted cookie variable.