I'm creating a checkout process with 4 pages, however i'm worried that a user may try to go back to previous pages of the checkout to modify and resubmit information in an attempt to manipulate information.
I heard about nonces but i cant really wrap my head around it. How would i link a nonce with a checkout? And how would this prevent a person from hopping to a random page of the checkout process using url (not using "go back" arrow on browser), wouldn't server side code create new nonce for that page when it is called and thus the person would still be able to modify information?
What i'm looking for is for a person to 1. not be able to randomly hop to any page of the checkout process (ex: at home page, then hop to the last page of checkout).And 2. not be able to go back to previous page of checkout process.
I'm looking for a very linear process that a user must start at a certain point (ex: a certain checkout button) or they will not have access to any of the checkout pages. They also must follow each checkout step in the right order. Any ideas of how this could be done?