you could add a random number to the encrypted data on the card and require it to always be the same or larger than the last time that card was seen, and then increment it every time the card is used.
The problem with that is that if the machines don’t talk to one another then there’s no way to make that system work across machines. I guess if each machine enforced it then you would eventually run out of machines that work for your hacked card.
you could add a random number to the encrypted data on the card and require it to always be the same or larger than the last time that card was seen, and then increment it every time the card is used.
The problem with that is that if the machines don’t talk to one another then there’s no way to make that system work across machines. I guess if each machine enforced it then you would eventually run out of machines that work for your hacked card.