Okay i'm a little bit stuck on how to solve this problem.

When a user registers. I want to send him a link so that he can verify hes email address.

But i have troubles generating the link.

I've already written the controller to accept the links with the correct keys. i only have no idea on how to generate the activation keys.

So when the user registers i'll send him a link by mail like this:

Your activation link is : http://site.com/user/verify?key=keyhere

Now i have created this method (called by the controller/action) to handle the key in the link:

 public string Verify(string value)
    {
        String email = Decrypt(value);

        user u = gebRep.GetUsers().WithEmail(email).SingleOrDefault();
        if (u != null)
        {
            u.emailValid = true;
            userReppository.Save();
        }

        return "Invallid validation value!";
    }

Now my problem is I have no idea on how to encrypt and decrypt the email into some sort of key (url friendly) So i can mail it with the link and can use it to verify the email.

I need some kind of (not to complicated but secure) way to encrypt the email into a urlfriendly key.

Tyvm