4 ms·

I don't think the suggestion is the QR code contains the ticket info, but that the QR code is the unique tag into the back end virtual ticket system. 1 to 3 are

I don't think the suggestion is the QR code contains the ticket info, but that the QR code is the unique tag into the back end virtual ticket system. 1 to 3 are not relevant in that context, and 4 isn't borne out in my experience with modern readers (they're used in the bar code mix at parkrun and they read time is vanishingly fast with a smart phone, generally better than barcodes). The number of bits might increase the difficulty if capturing the code, but I would very surprised if a fast, robust system can't be built. The huge disadvantage of NFC in this context is the electronic waste necessarily produced.

sverhagen 2y ago
> and 4 isn't borne out in my experience To bolster your point, aren't there whole countries where stores and street sales float on top of QR codes?
- matsimitsu 2y ago
  In China, QR Codes are used for public transport too, and I found them just as fast as NFC readers (and faster than the slow readers used by the NS in The Netherlands)
  - ralferoo 2y ago
    Until you go to another city and discover that the local bus company has decided that instead of just letting you pay by Wechat pay or Alipay, you need to install their proprietary app to generate the QR code for the bus to scan, at which point the app then just turns it into a Wechat pay or Alipay transaction at the end. No benefit to the user, it just allows the bus company to extract all your PII in the process. Actually, they're not all proprietary apps, but there are several from competing companies, and you have to use whichever one the city has chosen. Actually, I think part of the reason is that so they know who's on the bus in case it's involved in an accident, because if you buy a ticket from a bus station for a "short distance" (so out of the city, but within about 40km), you also have to provide them with a phone number even though they never call you or send you an SMS using that number.
    - pizzalife 2y ago
      >Actually, I think part of the reason is that so they know who's on the bus in case it's involved in an accident The CCP certainly do want to know who's on the bus, but not for the reasons you stated.
- defrost 2y ago
  Yes- of interest: China's Big Tech companies taught Asia to pay by scanning QR codes, but made a mess along the way https://www.theregister.com/2024/06/17/asia_qr_code_obsession/ https://www.theregister.com/2024/06/17/asia_qr_code_obsessio...
- rswail 2y ago
  Those QR codes are validated online. Transit has to work offline.
- rswail 2y ago
  The time to process a payment at a retail outlet is ~1s+, the time required for public transport is usually <0.5s including mechanical release of barriers etc. QRs are dramatically slower than NFC.
account42 2y ago
An always-online requirement is not feasible everywhere.
- kevincox 2y ago
  You can fail open. The QR code contained a signed ticket ID and expiry. You locally validate the signature and expiry and remotely attempt to validate reuse. If the remote validation is slow or fails just accept the ticket and log it.
  - rswail 2y ago
    That is what happens, however it exposes the transit company to a risk that many of them aren't willing to accept.
bunderbunder 2y ago
NFC doesn't necessarily create any additional e-waste. In Chicago we have an NFC system, and people typically just link their phone to their account and use that to pay. I still use a physical card - so that I have a backup option in case something happens to my phone - but even there the volume of waste is trivial. I've had my current transit card for ages, and it doesn't expire until 2037. It's possible that the only technological decision I've made that generated less e-waste was deciding to splurge on a mechanical watch instead of a quartz model.
- hgomersall 2y ago
  Well, yes, but the article is about a disposable nfc ticket.
  - bunderbunder 2y ago
    Those are more for single rides by people who rarely or never use the transit system. I've had the same Carte Opus for years and just bring it with me and refill whenever I visit Montreal. And the disposable paper cards are being phased out. I'm not sure when the rollout will be, but Montreal is currently working on upgrading the system to allow people to just tap-to-pay at the turnstiles using their phones or compatible credit and debit cards. Which is not something that you could do with a QR system. I don't know that anything is inherently wrong with QR codes, but they do seem to be a choice that's more appropriate for countries like China where the existing electronic payment infrastructure uses QR codes. In North America, by contrast, things have generally settled on NFC, and I think that that reason alone probably makes NFC the better option for North American transit systems.
    - efreak 2y ago
      > Montreal is currently working on upgrading the system to allow people to just tap-to-pay at the turnstiles using their phones or compatible credit and debit cards. > Which is not something that you could do with a QR system I've got several apps that display QR codes on the screen for an external reader. One of them is for my health insurance id card (a simple 10 digit number), another shows my COVID vaccination status (this one is complicated, and I'm not sure why they used a QR code for it. It must include batch identification and other information given the size)
rswail 2y ago
The problem with expecting a "unique tag into the back end" is that these systems have to work offline. The QR codes are significantly slower to read than NFC. I've built both NFC and QR (and ye olde fashioned magnetic stripe) ticketing systems.

sverhagen 2y ago

> and 4 isn't borne out in my experience To bolster your point, aren't there whole countries where stores and street sales float on top of QR codes?

matsimitsu 2y ago
In China, QR Codes are used for public transport too, and I found them just as fast as NFC readers (and faster than the slow readers used by the NS in The Netherlands)
- ralferoo 2y ago
  Until you go to another city and discover that the local bus company has decided that instead of just letting you pay by Wechat pay or Alipay, you need to install their proprietary app to generate the QR code for the bus to scan, at which point the app then just turns it into a Wechat pay or Alipay transaction at the end. No benefit to the user, it just allows the bus company to extract all your PII in the process. Actually, they're not all proprietary apps, but there are several from competing companies, and you have to use whichever one the city has chosen. Actually, I think part of the reason is that so they know who's on the bus in case it's involved in an accident, because if you buy a ticket from a bus station for a "short distance" (so out of the city, but within about 40km), you also have to provide them with a phone number even though they never call you or send you an SMS using that number.
  - pizzalife 2y ago
    >Actually, I think part of the reason is that so they know who's on the bus in case it's involved in an accident The CCP certainly do want to know who's on the bus, but not for the reasons you stated.
defrost 2y ago
Yes- of interest: China's Big Tech companies taught Asia to pay by scanning QR codes, but made a mess along the way https://www.theregister.com/2024/06/17/asia_qr_code_obsession/ https://www.theregister.com/2024/06/17/asia_qr_code_obsessio...
rswail 2y ago
Those QR codes are validated online. Transit has to work offline.
rswail 2y ago
The time to process a payment at a retail outlet is ~1s+, the time required for public transport is usually <0.5s including mechanical release of barriers etc. QRs are dramatically slower than NFC.

account42 2y ago

An always-online requirement is not feasible everywhere.

kevincox 2y ago
You can fail open. The QR code contained a signed ticket ID and expiry. You locally validate the signature and expiry and remotely attempt to validate reuse. If the remote validation is slow or fails just accept the ticket and log it.
- rswail 2y ago
  That is what happens, however it exposes the transit company to a risk that many of them aren't willing to accept.

bunderbunder 2y ago

NFC doesn't necessarily create any additional e-waste. In Chicago we have an NFC system, and people typically just link their phone to their account and use that to pay. I still use a physical card - so that I have a backup option in case something happens to my phone - but even there the volume of waste is trivial. I've had my current transit card for ages, and it doesn't expire until 2037. It's possible that the only technological decision I've made that generated less e-waste was deciding to splurge on a mechanical watch instead of a quartz model.

hgomersall 2y ago
Well, yes, but the article is about a disposable nfc ticket.
- bunderbunder 2y ago
  Those are more for single rides by people who rarely or never use the transit system. I've had the same Carte Opus for years and just bring it with me and refill whenever I visit Montreal. And the disposable paper cards are being phased out. I'm not sure when the rollout will be, but Montreal is currently working on upgrading the system to allow people to just tap-to-pay at the turnstiles using their phones or compatible credit and debit cards. Which is not something that you could do with a QR system. I don't know that anything is inherently wrong with QR codes, but they do seem to be a choice that's more appropriate for countries like China where the existing electronic payment infrastructure uses QR codes. In North America, by contrast, things have generally settled on NFC, and I think that that reason alone probably makes NFC the better option for North American transit systems.
  - efreak 2y ago
    > Montreal is currently working on upgrading the system to allow people to just tap-to-pay at the turnstiles using their phones or compatible credit and debit cards. > Which is not something that you could do with a QR system I've got several apps that display QR codes on the screen for an external reader. One of them is for my health insurance id card (a simple 10 digit number), another shows my COVID vaccination status (this one is complicated, and I'm not sure why they used a QR code for it. It must include batch identification and other information given the size)

rswail 2y ago

The problem with expecting a "unique tag into the back end" is that these systems have to work offline. The QR codes are significantly slower to read than NFC. I've built both NFC and QR (and ye olde fashioned magnetic stripe) ticketing systems.