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> No one said you can overdraw your account False: The qz article I'm responding to says this. "When you pull cash from an ATM or swipe your card at the coffe
by whoknowswhat11 5y ago
> No one said you can overdraw your account
False: The qz article I'm responding to says this.
"When you pull cash from an ATM or swipe your card at the coffee shop, the machine needs to determine the precise time that the transaction occurs to, for example, prevent it from being over-drawn."
Please please explain how this "over-drawn" situation occurs because of a GPS satellite.
> but if the clock is off on them vs the server they will fail, I have worked on a lot of payment systems.
False, CC terminal clocks do not need to be GPS time accurate. When the terminal connects to authenticate, they can update their time. There can be issues with authentication if clock skew is bad, but this requires normal levels of time sync (ie, NTP without GPS will be fine).
- dogma1138 5y agoWhile the reason is not necessarily correct (although it’s more of an over simplification than an outright error) the terminal needs to have the correct time if not the transaction would not be processed for a myriad of reasons. The issue is that in the vast chain of networks that a single transaction flows through you have multiple NTP servers each of them taking their own time form a different source which is often backed by GPS. If GPS services are disrupted globally this would cause payment networks to break down. Yes there would be a way to recover from it and move away from GPS but you are still missing the point on day-0 of a GPS blackout the global financial system would go down and it would be a mess and it wouldn’t be a mess that is easily sorted…