I am trying to delevop a script. This script is basically a script to prevent the same person from going to my incentive based link & completing the offer over & over again. So i need to place a "cookie" that is extremely hard for them to delete.

I am not trying to put anything malicious on their computer. I am just trying to determine if that user is already in my system or not.

Any ideas on if this is possible or how i can do this?

I was told that a flash based cookie might owrk.