Parking Meter Debit Cards

Parking Meter Debit Cards behave very similarly to standard memory cards, however they also have to provide some basic security to make sure people can't get free parking. This is done by using a method similar to the European Telephone Cards (SLE4406) where there is a section of memory on the card that acts as a one-way counter where bits are set to a certain amount of credits, then a security fuse is blown, and now the set bits can only be flipped from 1 -> 0. This is a standard security mechanism that makes it so people cannot recharge their cards once the credits have been used. The only catch is that the way that the parking meters work makes it so you can refund unused credits to the card.