My university had something similar, but with ID numbers correlated to each person in a database that recorded how many credits they had left.
Tapping the vending machine with your card sends the ID in plaintext over the wire to the upstream server, which responds in plaintext for the machine to either accept or reject the transaction.
Tomfoolery may or may not have been performed by a bunch of bored, hungry college students at 1AM one night...
Tapping the vending machine with your card sends the ID in plaintext over the wire to the upstream server, which responds in plaintext for the machine to either accept or reject the transaction.
Tomfoolery may or may not have been performed by a bunch of bored, hungry college students at 1AM one night...