How can you generate a new cookie value, with each new request (e.g. the cookie value changes when you click on a hyperlink).
An example would be something that PEAR AUTH does:
"Each client request a special unique cookie is given to the client. He must present this cookie on his next request. This cookie changes on every request. If client does not present the valid cookie he will be logged out."
Basically how could that ^ be done?