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The tiny chip that powers Montreal subway tickets

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Re: The tiny chip that powers Montreal subway tickets

#371

Post by grishka »

tombot wrote: post #337
grishka wrote: post #230

Earlier quoted context omitted.

The problem with QR codes is that they are read-only. I don't know about Montreal, but Moscow public transport uses similar paper tickets, also Mifare Ultralight, except you can get them for different number of trips. When you use your ticket, the turnstile or validator would increment those one-way counters so that the next one would know how many trips you have left. You can't do that with a QR code without either…

>You can't do that with a QR code without either the reader or the user's device having a persistent internet connection to some sort of central server that would keep track of all tickets, which is impractical. This is literally how all of the UK Mobile Train Tickets work. The ticket is a 2D barcode either on screen or on paper. Every gate / scanner operated by a guard records when the ticket has been scanned. They…

But that's a train that goes outside of the city or between cities. You usually buy a ticket specifically for the route you're taking so no system-wide synchronization is necessary, only the origin station needs to know that you've used that ticket.

Re: The tiny chip that powers Montreal subway tickets

#372

Post by delfinom »

BiteCode_dev wrote: post #342
solarized wrote: post #324

To peoples asking: "Why not just QR codes?" Again it's all about latency. QR codes take longer when you tap them at the gate: opening the app, waiting for the scanner to adjust, connecting to inet. While NFC handle these tasks almost instantly. A big difference in super busy places where queues are a nightmare. Again, this problem wouldn't exist if we can optimize WFH methods. We don't need to solving "physical probl…

I can't see big technical limitations resulting in slow QRCode scanning. We manage to detect fast cars going 120mph to fine them, we can read fingerprints instantly through a screen. We can take pictures of galaxies light years away. 30 years ago you could kill ducks with the NES guns instantly and it worked by detecting pixels. I'm sure we can figure out how to analyze black squares and turn them into a number under…

Lol, that's the joke.

QR Codes were invented by Denso (automaker own) / Toyota. For high speed assembly line processes. Lul.

Re: The tiny chip that powers Montreal subway tickets

#373

Post by delfinom »

a-dub wrote: post #348
solarized wrote: post #324

To peoples asking: "Why not just QR codes?" Again it's all about latency. QR codes take longer when you tap them at the gate: opening the app, waiting for the scanner to adjust, connecting to inet. While NFC handle these tasks almost instantly. A big difference in super busy places where queues are a nightmare. Again, this problem wouldn't exist if we can optimize WFH methods. We don't need to solving "physical probl…

NYC OMNY allows for direct payment from a debit/credit card via NFC at the turnstile. this has privacy issues but i think they're ameliorated if you use a smartphone. i think you can buy a transit payment card if you need one. no paper tickets. cool ephemera but pretty wasteful. would be pretty cool if/when we see a day where provably private cryptocurrency microtransactions allow for both real privacy and the 7 day…

Crypto isn't private as traceability is an inherent requirement for crypto to operate.

Anyway with OMNY.

You just buy a OMNY card and load it with cash if you want privacy. They are being slow to roll the vending machines for these out due to vendor issues but it's growing and they can't discontinue the MetroCard until they have all the vending machines in place.

Re: The tiny chip that powers Montreal subway tickets

#374

Post by Delk »

solarized wrote: post #324

To peoples asking: "Why not just QR codes?" Again it's all about latency. QR codes take longer when you tap them at the gate: opening the app, waiting for the scanner to adjust, connecting to inet. While NFC handle these tasks almost instantly. A big difference in super busy places where queues are a nightmare. Again, this problem wouldn't exist if we can optimize WFH methods. We don't need to solving "physical probl…

I'm not sure that necessarily explains the need for single-use NFC tickets, though. There could be a more durable serial-use or permanent card with NFC that regular commuters could buy, and if those commuters are the vast majority of rush hour passengers, it might not be such a problem if single-use tickets had a slightly slower system.

Of course that'd mean having two recognition mechanisms, so the operator might opt for NFC and chips for single-use tickets anyway to make the system simpler. But somehow having single-use tickets with chips on them does seem wasteful to me.

Re: The tiny chip that powers Montreal subway tickets

#375

Post by account42 »

lxgr wrote: post #191
lmz wrote: post #151

Earlier quoted context omitted.

EMV (specifically EMV contactless) is also based on ISO 14443, it's more like an application layer protocol on top of it. Apple Pay Express is just Apple Pay without the need for the full system UI: "If iOS isn’t in use because iPhone needs to be charged, there may still be enough power in the battery to support Express Card transactions." it interacts the same way as the physical card equivalent (otherwise they woul…

Both EMV and MIFARE (and similar solutions) indeed sit on top of ISO 14443-4 (or -3 for the older/lighter MIFARE versions), but they're conceptually very different: EMV is an account-based payments protocol, and the card only confirms its presence in a transaction; balances are managed on the backend. The reader does not authenticate itself to the card at all. MIFARE is a stored-value service and as such keeps track…

> MIFARE is a stored-value service and as such keeps track of the card's balance on-chip. This requires another smartcard on the reader side, holding the necessary keys for mutual authentication, but allows two-sided offline transactions, which is quite useful for transit applications (e.g. buses dropping out of network coverage, allowing higher volumes even during short server outages etc.)

MIFARE cards are used in all kinds of applications and not all of them require the reader to authenticate itself. And even in authenticated uses the keys don't neccessarily need to be stored in a smartcard (SAM) depending on the security requirements. For the simpler MIFARE cards a secure enclave for the keys doesn't even provide any additional security since they key is transmitted to the card anyway - and the simplest ones don't have any authentication at all.

Re: The tiny chip that powers Montreal subway tickets

#376

Post by sleepydog »

sippeangelo wrote: post #355
BiteCode_dev wrote: post #342

Earlier quoted context omitted.

I can't see big technical limitations resulting in slow QRCode scanning. We manage to detect fast cars going 120mph to fine them, we can read fingerprints instantly through a screen. We can take pictures of galaxies light years away. 30 years ago you could kill ducks with the NES guns instantly and it worked by detecting pixels. I'm sure we can figure out how to analyze black squares and turn them into a number under…

The Stockholm Metro and public transport uses QRs, but on phones, and it's awful. The huge variance in people's shitty broken, dim phones make it take 3-4 tries sometimes. Infuriating! The scanners themselves are brilliant though, but nobody wants to stand in line for some printer machine and need to carry a flimsy bit of paper around.

When I was there they also had NFC readers you can tap your credit card or phone on.

Re: The tiny chip that powers Montreal subway tickets

#377

Post by videogreg93 »

Delk wrote: post #374
solarized wrote: post #324

To peoples asking: "Why not just QR codes?" Again it's all about latency. QR codes take longer when you tap them at the gate: opening the app, waiting for the scanner to adjust, connecting to inet. While NFC handle these tasks almost instantly. A big difference in super busy places where queues are a nightmare. Again, this problem wouldn't exist if we can optimize WFH methods. We don't need to solving "physical probl…

I'm not sure that necessarily explains the need for single-use NFC tickets, though. There could be a more durable serial-use or permanent card with NFC that regular commuters could buy, and if those commuters are the vast majority of rush hour passengers, it might not be such a problem if single-use tickets had a slightly slower system. Of course that'd mean having two recognition mechanisms, so the operator might op…

Can confirm that in Montreal there is a permanent version of this card (la carte OPUS) on which you can reload more tickets.

There are even semi permanent ones you can buy, which are good for say 1 day, 1 weekend, or contain 10 passes.

Re: The tiny chip that powers Montreal subway tickets

#378

Post by account42 »

throwadobe wrote: post #233
kens wrote: post #2

Author here for all your NFC chip questions :-)

How much cheaper and smaller can they get before we see them used in parcel and freight?

You already see RFID tags used in retail so I would not be surprised if that isn't already the case somewhere in the shipping industry as well.

I imagine those can use even simpler chips that are completely read-only over the air and only have a UID programmed.

Re: The tiny chip that powers Montreal subway tickets

#379

Post by account42 »

lxgr wrote: post #249
jcynix wrote: post #71

Earlier quoted context omitted.

Single tap cards are usually just used with their "hardwired" chip serial number. That is stored in a central system which invalidates the number once you used it. This makes it rather easy (even if its environmentally unfriendly) to issue these cards: load a number of cards into your machine, register the serial number and invalidate it when used.

That's no longer the case: Many of the newer single-use ticket ICs (including the MIFARE Ultralight one mentioned in the article) actually support data storage and (very) basic cloning protection.

That the chips support data storage doesn't mean that that feature is used. There are systems that use MIFARE Ultralight cards for the UID alone just because they are cheap and easily sourced.

Re: The tiny chip that powers Montreal subway tickets

#380

Post by grugagag »

skeeter2020 wrote: post #370
dghughes wrote: post #368

Earlier quoted context omitted.

I was watching a travel show about France and in Paris it seems tourists can get confused as to where their ticket is for. They can easily end up on a train in an area their ticket isn't for. You get a 100 Euro fine! And that's an honest mistake not trying to get away without buying a ticket.

100 Euros for a travel story you'll tell years into the future, and funding the tourism economy - win-win!

100 Euros per person. A group of 7 would be 700 and that is only one mishap, there could be multiple per day..
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