form temparing Payment

I have a payment for开发者_运维技巧m which calculates payment on the selection of some items on the page and final amount to pay goes to payment gateway from an hidden field in the form. If user changes the amount by inspecting DOM, my form submits the changes amount and same goes to payment gateway. How can I secure my form for this temparing.

Thanks Umar

If you put the amount in the form you basically can't stop someone from manipulating it. You need to find a way to send the form data from the server side or your payment gateway provider should provide a way to validate the amount is correct through use of a hash or some other mechanism. You should ask your provider what options they offer to you along those lines.