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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

#351

Post by hlandau »

Gibbon1 wrote: post #97
hlandau wrote: post #73

The NFC chip I want still doesn't exist: a CPU and flash I can write a program for, directly, no VMs, no Java, without an NDA'd datasheet. These exist, but they're all behind NDAs and you're not allowed to have them. They're used for e.g. EMV.

I saw an NFC chip that has 512 bytes of eeprom. Talks to a micro via I2C and has an interrupt that can be used to wake it up. I think it's a M24LR04E. Costs like $0.50. I think these could be useful for devices where you have a limited amount of data you want to read or transfer. Like why have bluetooth and all the crap that entails when all you want to do is configure a device once. Advantage of a separate IC is you…

See comment below.

More generally what I'm seeking is something in the card form factor which is suitable to store cryptographic secrets (i.e., a smartcard).

Separate IC is a disadvantage here since it creates a vulnerable security boundary and makes it infeasible to integrate the chip into a thin card.

Re: The tiny chip that powers Montreal subway tickets

#352

Post by account42 »

hgomersall wrote: post #294
rswail wrote: post #289

Earlier quoted context omitted.

I've worked in public transport ticketing for the past 30 years including the first system outside Japan (Hong Kong's Octopus). The problem with QR codes: 1. If they're printed, they can be copied. 2. "Dynamic" QR codes can be screenshot. 3. They're read-only (by definition) 4. Readers are slow, require good orientation by the user. NFC is good because it's read/write, has a ~10cm range, the larger cards can hold up…

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…

An always-online requirement is not feasible everywhere.

Re: The tiny chip that powers Montreal subway tickets

#353

Post by teknologist »

scoot wrote: post #336
teknologist wrote: post #317

Earlier quoted context omitted.

I’ve found NDEF cards that can hold 16KB & 32KB, even as much as 64KB. That may be too much capacity for ticketing but it blows QR codes out of the water

When all you need is a unique identifier, what's the advantage?

None in that case. But with these cards there’s less need for centralization of data storage and code logic

Re: The tiny chip that powers Montreal subway tickets

#354

Post by bregma »

oopsallmagic wrote: post #194
ghaff wrote: post #149

Earlier quoted context omitted.

It's getting better but, in my experience, once metro systems got away from manned booths and tokens, the systems worked fine for commuters but led to lots of fumbling and long lines for tourists. Trains in the UK still have a certain amount of "Which of these tickets/receipts go where?" while a line of irritated locals is building up behind you. Fortunately, also being the UK, someone will help you if you're struggl…

Is that the fault of the system, or the fault of the tourists for visiting a new place and not reading up on local customs?

I recently visited Paris. I read up and watched videos on how to use the metro. They didn't really cover many of the important local customs: I let people off the train before trying to cram in and I held the exit gates open on my way out of a station so they didn't slam in the next person's face. I must have stuck out as a tourist. The "act like a local" public info available is never sufficient.

Re: The tiny chip that powers Montreal subway tickets

#355

Post by sippeangelo »

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…

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.

Re: The tiny chip that powers Montreal subway tickets

#356

Post by account42 »

TheJoeMan wrote: post #106
justusthane wrote: post #21

This is fascinating. We were just in Europe where we experienced these tickets for the first time. I had trouble with them; I was trying to figure out how to scan them because it never occurred to me that they might contain an NFC chip. My wife, on the other hand, who is not at all technical, took it for granted that you would tap them and immediately figured it out intuitively.

Does the card not have the three-arcs nfc symbol? Similar to the wifi symbol. To me the fake printed dip-chip is more confusing!

My guess would be that they used plastic chip cards before (those often also do NFC) and only switched to the paper cards later - at which point they either deliberately copied the whole design including the chip contacts to make the switch as unnoticeable as possible or just lost or couldn't be bothered to find the original design files and scanned an existing card for the print template.

Re: The tiny chip that powers Montreal subway tickets

#357

Post by kevincox »

account42 wrote: post #352
hgomersall wrote: post #294

Earlier quoted context omitted.

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…

An always-online requirement is not feasible everywhere.

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.

Re: The tiny chip that powers Montreal subway tickets

#358

Post by ghaff »

oopsallmagic wrote: post #194
ghaff wrote: post #149

Earlier quoted context omitted.

It's getting better but, in my experience, once metro systems got away from manned booths and tokens, the systems worked fine for commuters but led to lots of fumbling and long lines for tourists. Trains in the UK still have a certain amount of "Which of these tickets/receipts go where?" while a line of irritated locals is building up behind you. Fortunately, also being the UK, someone will help you if you're struggl…

Is that the fault of the system, or the fault of the tourists for visiting a new place and not reading up on local customs?

Ah, yes. The good old "It's the user's fault for holding it wrong."

Re: The tiny chip that powers Montreal subway tickets

#359

Post by fennecfoxy »

asah wrote: post #327
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…

1000s of people leaving a stadium faces the same latency: not a WFH/WFO issue

Not really a comparable thing versus the morning/evening rush every single weekday when forcing people in-office. It's the scale that makes it an issue, 1000s of people is nothing and more of an occasional spike.

See how London deals with toob stations for pride, for example, by closing and controlling some, exit only periods close to the event, open ticket gates, etc.

Re: The tiny chip that powers Montreal subway tickets

#360

Post by kevincox »

jszymborski wrote: post #265
CraigJPerry wrote: post #227

QR codes seem like a better ticket medium. This is like a 100 bytes, a qr code can be over 2kb This is a cheap plastic substrate with ink printing over the top. A qr code is just ink - or some other even cheaper printing process if you prefer. This needs a specific ticket technology supplier over the next 10’s of years. QR codes can be drawn on screens or printed on paper and you can change suppliers for every compon…

My understanding is that the STM (runs the Métro) likes to keep fares on the actual paper tickets or rechargeable card, rather than in some central database. The paper tickets can hold many fares, including unlimited evening fares or two day fares. I believe this would be hard to pull off with QR codes without having to keep track centrally.

Unlimited fares should be extra easy with a QR code. Just put a signed expiration date.

If course duplication is probably a bigger risk for these tickets as they case be simply locked to one use server side.

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