4 ms·

It's more complex than that: The card actually has some nonvolatile storage with your current balance, which gets decremented each time you use it.

lxgr 1y ago
Yes, stored value cards are a very mature technology. For various reasons, they're mostly used in closed-loop systems these days (think laundromats, transit systems etc.), but historically there were open-loop deployments in many European countries, and in some countries, stored-value POS payments are still very popular, e.g. in Japan. It's a real shame that the entire world moved to online-only. Sure, it's much easier and there's less opportunity for various kinds of fraud as a result, but in terms of availability during outages or cyber attacks, it was a big unforced step backwards.
- Galanwe 1y ago
  > historically there were open-loop deployments in many European countries Indeed, there used to be things like "Moneo". The problem is that banks never trusted really these systems, so you were limited to, say, 50E of stored value. Also for some reason in Europe the readers of such cards have never been great, I guess because most devices were built on the cheap, so even if the transaction is offline and supposedly fast, you would have to wiggle your cards all around most readers for 2s until it's picked up. In Hong Kong there is the Octopus card, which started as a closed loop subway card, but ended up being so loved that now you can pay litterally anything with it. It can store up to $500, and you can set it up to automatically top-up to $500 more per day linked to your bank account. Also accepting payments from octopus cards is very easy, you don't need a physical device and small businesses can just have the customer card tapped on their phone with a merchant app.
- mytailorisrich 1y ago
  Stored values cards were the way French public phone booths worked when they first moved away from coins in the 80s. There were single-use chip cards that you bought and kept in your wallet. Plain eeprom. I remember I built a reader for them as a teenager...
  - lxgr 1y ago
    These were storage only though, right? Such systems are trivial to compromise. Stored-value payment cards usually contain at least a secret key and some logic that allows them to establish a secure channel to another trusted entity, such as a merchant smartcard (which can be embedded in a terminal) or a backend server (and a corresponding HSM).
andrewshadura 1y ago
Not in the Netherlands, no. The card can be a bank card, and you can be billed at the end of the month automatically through direct debit. It also wouldn't work as you describe, as the terminal at the point of entry doesn't know how much to charge you since it doesn't know where your journey ends.
- tempay 1y ago
  Some transit systems work by putting a hold on your card for a nominal amount. When you finish your journey it then only claims the cost of your journey
  - ricardobeat 1y ago
    Thankfully that’s not the system GVB uses, it’s incredibly annoying to have these transactions and reversals when trying to do your own accounting.
    - netsharc 1y ago
      Holds don't really show up in the monthly statement. At least not in the cards I've had. It's a functionality for merchants to say "I'd like to charge this customer up to $500, would she be good for it?". If the CC company says yes, then the merchant knows they can do so. E.g. car rental companies do this for potential damages. Up to a week the merchant can charge the actual amount (usually less) or just release the hold.
      - sverhagen 1y ago
        Holds are a credit card feature, GVB is a Dutch transit authority, so they're more likely to be talking about bank cards, ie. debit cards, which I don't think support holds in that same sense.
- j4hdufd8 1y ago
  It definitely exists in Amsterdam, no? When I visit I just tap my card/phone on NFC enabled card checking machines (which exist in and out of the stations)
raducu 1y ago
> The card actually has some nonvolatile storage with your current balance. I'm not trying to find a gotcha, but wonder how that works with paying by phone nfc and then by card?
lmz 1y ago
There's stored value and then there's "account based ticketing" where your card is just an ID and the final amount will be debited daily.

lxgr 1y ago

Yes, stored value cards are a very mature technology. For various reasons, they're mostly used in closed-loop systems these days (think laundromats, transit systems etc.), but historically there were open-loop deployments in many European countries, and in some countries, stored-value POS payments are still very popular, e.g. in Japan. It's a real shame that the entire world moved to online-only. Sure, it's much easier and there's less opportunity for various kinds of fraud as a result, but in terms of availability during outages or cyber attacks, it was a big unforced step backwards.

Galanwe 1y ago
> historically there were open-loop deployments in many European countries Indeed, there used to be things like "Moneo". The problem is that banks never trusted really these systems, so you were limited to, say, 50E of stored value. Also for some reason in Europe the readers of such cards have never been great, I guess because most devices were built on the cheap, so even if the transaction is offline and supposedly fast, you would have to wiggle your cards all around most readers for 2s until it's picked up. In Hong Kong there is the Octopus card, which started as a closed loop subway card, but ended up being so loved that now you can pay litterally anything with it. It can store up to $500, and you can set it up to automatically top-up to $500 more per day linked to your bank account. Also accepting payments from octopus cards is very easy, you don't need a physical device and small businesses can just have the customer card tapped on their phone with a merchant app.
mytailorisrich 1y ago
Stored values cards were the way French public phone booths worked when they first moved away from coins in the 80s. There were single-use chip cards that you bought and kept in your wallet. Plain eeprom. I remember I built a reader for them as a teenager...
- lxgr 1y ago
  These were storage only though, right? Such systems are trivial to compromise. Stored-value payment cards usually contain at least a secret key and some logic that allows them to establish a secure channel to another trusted entity, such as a merchant smartcard (which can be embedded in a terminal) or a backend server (and a corresponding HSM).

andrewshadura 1y ago

Not in the Netherlands, no. The card can be a bank card, and you can be billed at the end of the month automatically through direct debit. It also wouldn't work as you describe, as the terminal at the point of entry doesn't know how much to charge you since it doesn't know where your journey ends.

tempay 1y ago
Some transit systems work by putting a hold on your card for a nominal amount. When you finish your journey it then only claims the cost of your journey
- ricardobeat 1y ago
  Thankfully that’s not the system GVB uses, it’s incredibly annoying to have these transactions and reversals when trying to do your own accounting.
  - netsharc 1y ago
    Holds don't really show up in the monthly statement. At least not in the cards I've had. It's a functionality for merchants to say "I'd like to charge this customer up to $500, would she be good for it?". If the CC company says yes, then the merchant knows they can do so. E.g. car rental companies do this for potential damages. Up to a week the merchant can charge the actual amount (usually less) or just release the hold.
    - sverhagen 1y ago
      Holds are a credit card feature, GVB is a Dutch transit authority, so they're more likely to be talking about bank cards, ie. debit cards, which I don't think support holds in that same sense.
j4hdufd8 1y ago
It definitely exists in Amsterdam, no? When I visit I just tap my card/phone on NFC enabled card checking machines (which exist in and out of the stations)

raducu 1y ago

> The card actually has some nonvolatile storage with your current balance. I'm not trying to find a gotcha, but wonder how that works with paying by phone nfc and then by card?

lmz 1y ago

There's stored value and then there's "account based ticketing" where your card is just an ID and the final amount will be debited daily.