I am developing a site with advertisements, users can place an advertisement for their products. Of course they have to be able to change his advertisement, so I made a page for changing the advertisement. I want to send a link to the users email address to the change page, I don’t want to use a password because there are already so many passwords to remember. Also the user can bookmark the link so he can access the change page quickly. Of course no one other than the user has to be able to access the changepage with the link, also with other computers/tablet so using the IP address is no option. How can I create a unique link witch is no to guess or intercept by hackers? I do have SSL/HTTPS possibilities….