7 ms·

So many ridiculous hacks upon hacks going on here. There is only ONE WAY to implement these payment systems and it was known to the designers of the smart card

So many ridiculous hacks upon hacks going on here. There is only ONE WAY to implement these payment systems and it was known to the designers of the smart card and related public-key crypto designers 40 years ago: the merchant must sign the transaction with their key, the user must inspect the signed transaction on their own trusted device and enter PIN to sign with their private key, and the whole thing is verified and cleared by the network operators. The pile of hacks we have today is just a result of the fact that the networks don't want to operate the PKI.

germanier 10y ago
Or more likely because customers don't want to inspect a transaction on their own device at the supermarket checkout or even worse a transport fare gate. A "solution" which takes minutes to perform is not a solution to the real-world problem.
- honkhonkpants 10y ago
  It's a tradeoff between speed and security. Anyway there's certainly no reason why minutes need be the case. A contactless smartcard with an integrated e-ink display and PIN pad would not take anywhere near the amount of time we currently suffer in the US implementation of chip and PIN. Edit: fare gate is a special class of problem. I don't expect TfL to be screwing with me, whereas I may be highly suspicious of the point-of-sale system down at the corner bodega.
  - sjtgraham 10y ago
    Totally unreasonable to implement. How are these cards supposed to run? They don't have batteries. Even if this was realistic to deploy it would be prohibitively expensive, far exceeding what it's costing banks to eat the fraud.
    - honkhonkpants 10y ago
      Why? Forget the e-ink for a moment and just use lcd instead. I once had an lcd calculator (no backlight, of course) that ran for a decade on a lithium battery. smart cards barely use any energy at all.
      - sjtgraham 10y ago
        Things a cheap calculator needs to do: - Simple arithmetic on an occasional basis Things a NFC card implementing the system you describe: - Radio - Public key crypto - ASN.1 DER X.509 parsing to validate the signed transaction from the terminal. The terminal would need to send a cert chain to the card and the card follow the chain to the network root to correctly verify the terminal signature. - Parsing OCSP responses, which the terminal would have to staple to its cert because the card has no other way of knowing the revocation status of the terminal cert. - Conform to ISO 7816 for interoperability with legacy equipment. - Fit in a wallet/purse/pocket - Be a reasonable cost
        honkhonkpants 10y ago
        I already have a cryptocard that does all that junk just from the RF power it gets off the terminal.
        sjtgraham 10y ago
        I bet it's not interactive. Interactivity powered by near field RF is impractical because power is lost when the card is out of range. This would result in some very awkward UX as users have to hold their card close enough to the reader for power while they verify the transaction metadata and enter their PIN.
        viraptor 10y ago
        Check with people who already use this: https://newsroom.mastercard.com/press-releases/mastercard-introduces-next-generation-display-card-technology-a-first-for-singapore/ https://newsroom.mastercard.com/press-releases/mastercard-in... Producer: https://www.nidsecurity.com/products/solution-financial.html https://www.nidsecurity.com/products/solution-financial.html
    - hatsunearu 10y ago
      Leach off the POS machine?
    - JaumeGreen 10y ago
      Cards like these exist[0], not sure if only as a concept. The cost of the card wouldn't be much, perhaps enough to pass it to the customer, but not outrageous. [0]http://newsroom.mastercard.com/press-releases/mastercard-introduces-next-generation-display-card-technology-a-first-for-singapore/ http://newsroom.mastercard.com/press-releases/mastercard-int...
viraptor 10y ago
> the user must inspect the signed transaction on their own trusted device I don't believe this has been ever implemented, or anyone knows how to do this really. How do you imagine it would work? Every card preloaded with every bank's CA? Cards connecting back to the issuer for updates? Something else? Basically a) signed with what, and b) what does "inspect" mean?
- honkhonkpants 10y ago
  The networks would delegate a cert to the merchant which the card can verify because it's loaded with the root/intermediate chain needed to do so. "Inspect" means you get to see the amount you're going to be charged.
  - viraptor 10y ago
    > The networks would delegate a cert to the merchant which the card can verify because it's loaded with the root/intermediate chain needed to do so. Revokation of CAs or intermediates would mean that many cards suddenly stop working before the expiry date. Can you imagine the PR fallout if that happens? > "Inspect" means you get to see the amount you're going to be charged. You still don't know who you're charged by. It could be another transaction relayed to you. It makes it less practical (synchronised payment / compromised terminal), but not impossible considering how many hoops we have to jump through for this class of attack in general.
    - honkhonkpants 10y ago
      They'd have to get the timing and the amount right.
    - Dylan16807 10y ago
      > Revokation of CAs or intermediates would mean that many cards suddenly stop working before the expiry date. Can you imagine the PR fallout if that happens? Revocation shouldn't make cards stop working, as long as certs are still signed with some valid chain. And new CAs can be cross-signed. The only thing that has to get updated is the merchant terminal config.
RubyPinch 10y ago
That is a bit silly, especially considering its bank money, not bitcoins Just have an app that allows the user to review transactions after they have happened. If there is a double charge, dispute and win easily, if charged too much, dispute and win easily, etc etc This already exists too
- deathanatos 10y ago
  > This already exists too The fraud resolution on my Visa card[1] required me to: 1. call the merchant that charged the fraudulent charge, and attempt to get them to void it. This was literally as pointless as it sounds. 2. Receive a specific form that could only be sent by snail mail or fax. The sending end absolutely refused to send it over email. Thankfully my building has a fax machine, and my building manager has common sense, and allowed me to borrow it. The fax service we use (because who uses fax?) turns faxes into — you guessed it — emails. Of course, at the bottom of the received fax is "H:\SharedDocs\Stuff\More Stuff\TheForm.pdf". 3. Fill it out, scan it back into a computer, fax the PDF back. (I could have also snail mailed it back.) 4. Receive a confirmation over snail mail, noting that it will be resolved sometime in the next 6 months. I never lost possession of my card, and the merchant who charged the card was able to confirm that the "card" was presented at the time of purchase (it was made physically, in a store) — while the real card rested in my wallet, thousands of miles away. I was issued a new card, of course, and the old one voided. The new card is still not chip and pin, despite me explicitly asking for it. I'd love to take on the "hassle" of public-key crypto. [1] This was a debit card that works as either a credit card or a debit card (though the latter mode requires a pin, but the former mode requires nothing … because … waves hand); I am told credit cards are supposedly less of a pain.
  - honkhonkpants 10y ago
    This is why nobody should use a debit card. With a credit card, I call my issuer, tell them that I don't owe the charge, and after that it's the merchant's problem.
    - deathanatos 10y ago

germanier 10y ago

Or more likely because customers don't want to inspect a transaction on their own device at the supermarket checkout or even worse a transport fare gate. A "solution" which takes minutes to perform is not a solution to the real-world problem.

honkhonkpants 10y ago
It's a tradeoff between speed and security. Anyway there's certainly no reason why minutes need be the case. A contactless smartcard with an integrated e-ink display and PIN pad would not take anywhere near the amount of time we currently suffer in the US implementation of chip and PIN. Edit: fare gate is a special class of problem. I don't expect TfL to be screwing with me, whereas I may be highly suspicious of the point-of-sale system down at the corner bodega.
- sjtgraham 10y ago
  Totally unreasonable to implement. How are these cards supposed to run? They don't have batteries. Even if this was realistic to deploy it would be prohibitively expensive, far exceeding what it's costing banks to eat the fraud.
  - honkhonkpants 10y ago
    Why? Forget the e-ink for a moment and just use lcd instead. I once had an lcd calculator (no backlight, of course) that ran for a decade on a lithium battery. smart cards barely use any energy at all.
    - sjtgraham 10y ago
      Things a cheap calculator needs to do: - Simple arithmetic on an occasional basis Things a NFC card implementing the system you describe: - Radio - Public key crypto - ASN.1 DER X.509 parsing to validate the signed transaction from the terminal. The terminal would need to send a cert chain to the card and the card follow the chain to the network root to correctly verify the terminal signature. - Parsing OCSP responses, which the terminal would have to staple to its cert because the card has no other way of knowing the revocation status of the terminal cert. - Conform to ISO 7816 for interoperability with legacy equipment. - Fit in a wallet/purse/pocket - Be a reasonable cost
      - honkhonkpants 10y ago
        I already have a cryptocard that does all that junk just from the RF power it gets off the terminal.
        sjtgraham 10y ago
        I bet it's not interactive. Interactivity powered by near field RF is impractical because power is lost when the card is out of range. This would result in some very awkward UX as users have to hold their card close enough to the reader for power while they verify the transaction metadata and enter their PIN.
        viraptor 10y ago
        Check with people who already use this: https://newsroom.mastercard.com/press-releases/mastercard-introduces-next-generation-display-card-technology-a-first-for-singapore/ https://newsroom.mastercard.com/press-releases/mastercard-in... Producer: https://www.nidsecurity.com/products/solution-financial.html https://www.nidsecurity.com/products/solution-financial.html
  - hatsunearu 10y ago
    Leach off the POS machine?
  - JaumeGreen 10y ago
    Cards like these exist[0], not sure if only as a concept. The cost of the card wouldn't be much, perhaps enough to pass it to the customer, but not outrageous. [0]http://newsroom.mastercard.com/press-releases/mastercard-introduces-next-generation-display-card-technology-a-first-for-singapore/ http://newsroom.mastercard.com/press-releases/mastercard-int...

viraptor 10y ago

> the user must inspect the signed transaction on their own trusted device I don't believe this has been ever implemented, or anyone knows how to do this really. How do you imagine it would work? Every card preloaded with every bank's CA? Cards connecting back to the issuer for updates? Something else? Basically a) signed with what, and b) what does "inspect" mean?

honkhonkpants 10y ago
The networks would delegate a cert to the merchant which the card can verify because it's loaded with the root/intermediate chain needed to do so. "Inspect" means you get to see the amount you're going to be charged.
- viraptor 10y ago
  > The networks would delegate a cert to the merchant which the card can verify because it's loaded with the root/intermediate chain needed to do so. Revokation of CAs or intermediates would mean that many cards suddenly stop working before the expiry date. Can you imagine the PR fallout if that happens? > "Inspect" means you get to see the amount you're going to be charged. You still don't know who you're charged by. It could be another transaction relayed to you. It makes it less practical (synchronised payment / compromised terminal), but not impossible considering how many hoops we have to jump through for this class of attack in general.
  - honkhonkpants 10y ago
    They'd have to get the timing and the amount right.
  - Dylan16807 10y ago
    > Revokation of CAs or intermediates would mean that many cards suddenly stop working before the expiry date. Can you imagine the PR fallout if that happens? Revocation shouldn't make cards stop working, as long as certs are still signed with some valid chain. And new CAs can be cross-signed. The only thing that has to get updated is the merchant terminal config.

RubyPinch 10y ago

That is a bit silly, especially considering its bank money, not bitcoins Just have an app that allows the user to review transactions after they have happened. If there is a double charge, dispute and win easily, if charged too much, dispute and win easily, etc etc This already exists too

deathanatos 10y ago
> This already exists too The fraud resolution on my Visa card[1] required me to: 1. call the merchant that charged the fraudulent charge, and attempt to get them to void it. This was literally as pointless as it sounds. 2. Receive a specific form that could only be sent by snail mail or fax. The sending end absolutely refused to send it over email. Thankfully my building has a fax machine, and my building manager has common sense, and allowed me to borrow it. The fax service we use (because who uses fax?) turns faxes into — you guessed it — emails. Of course, at the bottom of the received fax is "H:\SharedDocs\Stuff\More Stuff\TheForm.pdf". 3. Fill it out, scan it back into a computer, fax the PDF back. (I could have also snail mailed it back.) 4. Receive a confirmation over snail mail, noting that it will be resolved sometime in the next 6 months. I never lost possession of my card, and the merchant who charged the card was able to confirm that the "card" was presented at the time of purchase (it was made physically, in a store) — while the real card rested in my wallet, thousands of miles away. I was issued a new card, of course, and the old one voided. The new card is still not chip and pin, despite me explicitly asking for it. I'd love to take on the "hassle" of public-key crypto. [1] This was a debit card that works as either a credit card or a debit card (though the latter mode requires a pin, but the former mode requires nothing … because … waves hand); I am told credit cards are supposedly less of a pain.
- honkhonkpants 10y ago
  This is why nobody should use a debit card. With a credit card, I call my issuer, tell them that I don't owe the charge, and after that it's the merchant's problem.
  - deathanatos 10y ago