I am looking for code that would force a user to use a serial number to download a digital download. The downloads would be protected from crawlers probably called via php. Once the serial number is used it cannot be used again. I'd need to setup serial numbers for multiple products. Keep in mind no payment is transfered its only a serial number. URL would need to be masked so people couldn't share the link. Nice to have would be reporting mechanism to show how many codes have been used and on which product. Also a way to reactivate codes that didn't get a complete download. PM if interested or respond here if you have more questions.