81–90 of 525 posts
Earlier quoted context omitted.
> Makes me get out of bed and tap my phone on a specific NFC tag placed somewhere around the house, in order to turn off the alarm. Neat, but is there an advantage between this and "Place the alarm clock further from the bed"?
The noise maker (alarm) is still close to him.
Comparing Montreal subway with Vancouver's skytrain: - Montreals subway stations have this gritty, distinctively french atmosphere i loved it. - Vancouvers above/below stations have no soul, distinctively anglo but above ground ones i liked. - Montreal train cars use rubber wheels to my shock! Extremely loud. - Vancouver train cars use some sort of electric system which im not familiar with ( have a few variants (new…
The Skytrain to YVR is indeed very nice - built for the winter Olympics. Maybe not as "connected" as some European airports but quite convenient.
The problem with transit in Vancouver is that most of it is rays emanating from downtown, i.e. you have fairly decent (though IMO worse than most large European cities) transit if you need to get downtown but it's terrible useless if you need to get across. My work used to be 20 minutes drive time, >2 hours transit time.
Skytrain doesn't exactly cover the entire region, as you get further away from the downtown core the coverage gets much spottier until when you get far enough (but still part of metro Vancouver) it's non-existent.
There are certainly times when buses don't show up on time. I take transit these days to work and back and I would say something like 30% of the time the bus isn't on time. About 5% of the time the bus I'm supposed to take just never shows up.
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.
> The Ultralight chip has a few features beyond a printed ticket, though. The chips are manufactured with a unique 7-byte identification code (UID). Moreover, the UID is signed, ensuring that fake UIDs cannot be generated. The problem is, they can be just as easily cloned . Your average Flipper Zero can do that. If you want actual security, you have to go for a challenge-response scheme - i.e. every card is provision…
It's utterly not worth it. Your time to get it working, the equipment... but even if you have all of those if you get caught they will throw the book on you to scare away others. You can be charged by Unauthorized use of computer, Fraud and who knows what else. All of that to save four dollars on a ticket? When every station has cameras?
Like what, there's Tiktoks advising young dumbasses precisely what they need to steal and joyride cars.
My favorite household NFC usage? NFC alarm clock. Makes me get out of bed and tap my phone on a specific NFC tag placed somewhere around the house, in order to turn off the alarm. Then, I may as well wake up, since I'm already out of bed : ) It's a nice companion to help perform 'habit stacking' as Atomic Habits calls it. Want to do pushups right after waking up? Place an NFC card under your workout mat, so you're fo…
My favorite household NFC usage? NFC alarm clock. Makes me get out of bed and tap my phone on a specific NFC tag placed somewhere around the house, in order to turn off the alarm. Then, I may as well wake up, since I'm already out of bed : ) It's a nice companion to help perform 'habit stacking' as Atomic Habits calls it. Want to do pushups right after waking up? Place an NFC card under your workout mat, so you're fo…
> The Ultralight chip has a few features beyond a printed ticket, though. The chips are manufactured with a unique 7-byte identification code (UID). Moreover, the UID is signed, ensuring that fake UIDs cannot be generated. The problem is, they can be just as easily cloned . Your average Flipper Zero can do that. If you want actual security, you have to go for a challenge-response scheme - i.e. every card is provision…
Another option is to just store used UIDs in a database. In fact, you could do a system with only UIDs. For a single use ticket, validate the UID signature and mark it as spent the first time it is used, then every use after that will be denied.
A card can be cloned, and it will work, once, it means one could steal a ticket by walking by and using appropriate equipment (not just a Flipper Zero as it is too short ranged) and use it before the legitimate owner does. I don't think it is something to worry about for a single use subway ticket.
To improve security for multi-use tickets, one could use rolling codes: every time a ticket is scanned and its UID validated, some code is read from the NFC memory and it has to match a sequence, the next code is then written back to memory and has to be provided next time, invalidating any clone. Tickets can still be stolen, but you can't beat the system unless you crack the server-side encryption.
More valuable tickets like commuter passes can use a different system with a challenge-response scheme.
Earlier quoted context omitted.
I don't think the password authentication helps against cloning. You could start a transaction and stop after you get the password. Then you could clone the card. (The system could invalidate the ticket as soon as they get the UID, but that would be a reliability nightmare since a failure during the read would invalidate someone's ticket.)
You could do that, but it still greatly raises the cost for an attacker, since they need to hang around a ticket validator for every ticket they want to clone, as opposed to e.g. a QR code ticket, which can be trivially copied by a simple screenshot. Also, many of these transit systems are eventually consistent (they're usually offline-capable for resilience, but usually manage to send all validation transactions to…
How is a chip like this actually manufactured? Especially the analogue components area.