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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

#281

Post by shiroiushi »

lxgr wrote: post #163
chgs wrote: post #123

Mifare is what’s been used in London’s Oyster cards for 20 years (not the ultralight ones mind), and Hong Kong for even longer. However oyster really is in its way out for most uses. contactless and especially a phone is far more convenient for non season use, and far less wasteful.

Hong Kong's Octopus card uses Felica, as far as I know. It's conceptually very similar to MIFARE – a fixed function IC implementing a fully offline stored value purse – but uses a stack that differs from ISO 14443 A on pretty much all layers. (It was planned to possibly become ISO 14443 C, but that never happened.)

>Hong Kong's Octopus card uses Felica, as far as I know.

Yes: Felica was developed by Sony in Japan, but was actually first adopted in Hong Kong, then later in Japan. It's far better than other standards, because it's so fast.

Re: The tiny chip that powers Montreal subway tickets

#282

Post by qaisjp »

kens wrote: post #2

Author here for all your NFC chip questions :-)

I really enjoyed this read, thanks.

In the footnotes you said:

> One complication is that the counters have an "anti-tearing" feature for additional security

Two questions:

1. Why is it a "complication"? Is it just that it makes the counters more complicated, or is there something frustrating about the counters? 2. I would love to learn more about how the anti-tearing feature works!

Re: The tiny chip that powers Montreal subway tickets

#283

Post by rjh29 »

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…

Your comment sounds good for overland rail, bus, event tickets, airlines etc and indeed QR is common.

But for subway/metro, during rush hour throughput it is important to able to tap an RFID almost instantly. QR is too slow and error-prone for subway/metro.

The world (including Montreal - these tickets are going away) has converged on credit card / phone / top-up charge card for that reason.

Re: The tiny chip that powers Montreal subway tickets

#284

Post by mav3ri3k »

grishka wrote: post #230
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…

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…

I am not sure which part is impractical. In India we already use QR code for metro tickets. The system design is definitely different from one mentioned and mimics more of how airport tickets work.

Re: The tiny chip that powers Montreal subway tickets

#285

Post by TowerTall »

amluto wrote: post #32

> Presumably, the makers thought that making the card look like a smart card would help people understand it. The card actually uses an entirely different technology. It’s kind of the same, though. The physical communication layer is different, but the higher protocol layers are basically identical. Smart cards with contacts follow ISO 7816. These MIFARE contactless cards are ISO 14443 Type A cards, and their protoco…

One of my claims to fame was being part of the team that built the first online banking site for a bank in my country around 1997.

One of the things you could do was pay certain types of widely used paper invoices. When I was brought on, the UI for this was just a standard HTML table with labels and input boxes. I decided to build a prototype with a paper invoice image as the background and a textboxes places where the numbers appearred on the paper invoice.

When people paid the invoice, they would have the paper version they had received by postal mail next to them. Now, their mission was to enter the numbers so they would end up with a visual one-to-one copy of the paper invoice on the computer screen. It made it easy for everyone to figure out which numbers to enter.

People embraced this immediately, and all forms were changed to follow this principle. All banks implemented it in their banking apps and still use it today.

Re: The tiny chip that powers Montreal subway tickets

#286

Post by microtonal »

jeffparsons wrote: post #252
vundercind wrote: post #172

Earlier quoted context omitted.

I’ve never seen them skip a step. Basically all other flat pack furniture I’ve ever bought has, but none of the dozen or so ikea items I’ve assembled. It’s part of why I only buy flat pack if it’s ikea, now.

I recently assembled two non-IKEA flat-packed items from two different vendors. One left out details in the diagrams in each step that they had deemed irrelevant to that step. This apparent attempt at simplifying the instructions stumped me for ages because I kept thinking I'd oriented pieces wrong due to the number of holes in the picture differing from the number of holes in the physical thing. The other had switch…

Also, their more expensive furniture can be of a pretty good quality (e.g. Idåsen for office furniture).

Re: The tiny chip that powers Montreal subway tickets

#287

Post by kumarvvr »

lxgr wrote: post #258
kumarvvr wrote: post #236

I am apalled at the crazy amount of waste this creates. Millions of tickets with chips inside them? My understanding is that they are one time use? In New Delhi metro, India, they used to use plastic tokens with these chips, but at the end of the journey, to exit the station you have to give the chip back. Nowadays, they use a printed QR system, and they have even gone paperless. I can buy the ticket with my mobile a…

I find the plastic tokens quite clever, but QR codes are not a great option for mobile ticketing at transit gates: Often it takes people forever to pull up the code in the right orientation and dial up the brightness enough for the scan to work. Not something I love to deal with when I want to catch a train.

QR code reading does not depend on the orientation, at-least as per its spec. there are many apps and devices out there that can read a QR code in any orientation.

In the app that is used by me, the brightness of the screen is automatically increased by the app as soon as I open the ticket QR, and then reduces to its previous state, once the QR code display is removed.

Re: The tiny chip that powers Montreal subway tickets

#288

Post by grishka »

mav3ri3k wrote: post #284
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…

I am not sure which part is impractical. In India we already use QR code for metro tickets. The system design is definitely different from one mentioned and mimics more of how airport tickets work.

How does the system know that the ticket was already used?

The thing with plane and long-distance train tickets is that you buy them for a specific route. So all the checking only needs to be done at your departure station/airport, the code for which is encoded in the ticket, and the rest of the system doesn't need to know anything about it. But you can't do that with city transport. When there aren't multi-use tickets, people would often buy multiple single-use ones at a time and use them as the need arises, without knowing in advance when, where, and from where they'll be going.

Re: The tiny chip that powers Montreal subway tickets

#289

Post by rswail »

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…

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 to 4K of data, the ultralights can replace single journey tickets and can be recycled like magnetics being captured at exit.

Re: The tiny chip that powers Montreal subway tickets

#290

Post by reitanuki »

rtpg wrote: post #274
Reason077 wrote: post #207

Earlier quoted context omitted.

Yes, the TfL system does a partial authorisation. It checks the card is valid and not blocked etc but doesn’t necessarily do a real-time authorisation all the way to the issuing bank. If you try to use a card that is valid but has no available balance/credit, it might work for the first ride but then be blocked when you try to use it for the return trip. Fares are batched throughout the day and you are charged once,…

Wonder how they block the card, my impression was that tokenization was meant to make it harder for card chargers to be able to track a card through multiple taps like that.

They must have the card identity because you have to explicitly 'tap out' at the other end, if you don't want to be billed with a maximum fare.

Don't ask me how though

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