Is there a way to recognize a computer without its IP?

[talika_g]

Well... Im building with someone a system, which will let people buy pages (information and guides) by sending a simple SMS. This system will contain a mini users registration system (without a password, only usernames), and the surfers in my system will be able to create a user in thier own computer, but not to log-in thier user in another computer (that's, acually, why i don't need a password). I can't allow my surfers to log-in in thier own user in more than 1 computer because of 1 simple reason: If I'll do that they'll just give thier user details to thier friends or for people they're know...I got 1 problem: Let's say I'm a surfer in this system, I created a user, and bought 2 pages by SMS, now I simply closed my computer, and when I opened it, my IP has been changed. Now, I can't see the pages I've just bought one day ago, and that's not exactly what I want, as surfer, or as manger!Cookies could help, but the surfers always can just send the cookies to thier friends or something... I can't allow that kind of thing, Ill just lose money if ill use cookiesI want to implement one of the following ideas:

• Make the surfers don't want to give people thier user details somehow
• Recognize a computer, but not with its IP ('cuz then the IP will simply change)...

Is there a possible way in PHP to solve my problem? maybe a way to save data in computers, so the users won't be able to change/delete/copy it? or maybe recognize computers by thier hostnames or something? sincerely, Tal.

[justsomeguy]

Details like this change, and you're going to ###### off your users if you don't let them do what they want to do (like access their account from anywhere). It would be best to store information, such as a credit card number, that they would not want to share. Or, have them use their last four credit card digits as part of the login. People wouldn't want to give that out I would imagine.