How to ENCRYPT dynamic parameter and pass it to URL after .aspx extension....

I current using some more stupid method, I hard code the parameter as code below...

I always set the parameter to byw5Vds and then put behind the url, then send the link to customer email address.

http://www.xxxx.com/incoming.aspx?byw5Vds=" + Session["CarNo"].ToString();



Then in the Incoming.aspx PageLoad part I use

Request.Params["byw5Vds"].ToString();

to retrieve my Session["CarNo"]


I want to make it more flexible and security... I want to make the parameter every time diffrent. Something like windows live mail...

and then how to make it when customer click the link it straight link to the page and login..

mean store user name to my Login Session --->>> Session["LoginName"] ???



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