So a while ago, I saw a video of a device being used to steal a car. This device was in two parts. One would be used to scan for any key signals in the house, and the other would be used to duplicate that signal and transmit it in order to unlock the car door.
I was wondering: would something similar to this be possible in the duplication of wireless cards? For example: What if, by finding the signal on a regular subway card, the signal can be changed and replicated by a device which would essentially grant you unlimited subway trips. (I know, sounds impossible. But is it really?)
I’d imagine this would not work if these cards were already on a digital registry which holds the card number (or whatever identifies the card) and a value associated to the card of how many trips that card has left. But there could be some way to circumvent this.
So how would the replication of a card signal work? Are the number of trips left stored on the card itself? If not, how do wireless subway cards *really* work?
^((In my own opinion although I’ve never done this, I’d expect subway card hacking to be easily accomplished given that there’s probably not much thought put into the security of the cards themselves.))