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True, on iOS access to the NFC chip has been a additional blocker. But on Android apps have been able to use the NFC chip just fine and it's still not that eas

True, on iOS access to the NFC chip has been a additional blocker. But on Android apps have been able to use the NFC chip just fine and it's still not that easy to write a generic "wallet" app (that's compatible with all banks & cards), see my previous comment.

charcircuit 2y ago
>But on Android apps have been able to use the NFC chip just fine The last time I looked at it, it was not possible because Android doesn't let apps control the uid that gets used for NFC.
- codethief 2y ago
  Ah right, good point. I did forget about that. Either way, even if apps had full control over the chip, my understanding is that building a wallet app would still amount to much more than just interfacing with the NFC chip.
  - dzikimarian 2y ago
    You need connection to card scheme, which means you need ton of paperwork, which means you need ton of money. That's biggest issue :-) For technical side - there are companies selling complete SDKs.
    - codethief 2y ago
      Could you elaborate? You seem like you know quite a bit about this topic. While I've known that building a wallet is not as simple as configuring the NFC chip and one would have to interface with banks on the backend etc., I've failed to understand exactly why. What prevents a phone from emulating a regular physical credit card?
      - dzikimarian 2y ago
        On technical level - nothing. Thing is, that payment card is basically private key, that's derived from master key controlled by the bank. This key signs your transactions. Tokenization adds some extra steps (eg. single use keys), but it's fundamentally the same. What it means - you cannot obtain working card profile if bank doesn't issue it to you. Therefore you need blessing from bank & card scheme to be connected to this ecosystem. If you want to go deeper into this rabbit hole I can recommend two sources: * https://developer.mastercard.com/product/mdes https://developer.mastercard.com/product/mdes - Mastercards framework for tokenization * https://developer.verestro.com/books/token-requestor https://developer.verestro.com/books/token-requestor - actual solution. It focuses on offering for single issuer, because market for Google Pay competition is pretty narrow, but technically it's mostly the same + way more red tape. If you ever decide to try - ping me, I happen to know a few guys there :-)
        codethief 1y ago
        Thank you so much! That's very enlightening! > If you ever decide to try - ping me, I happen to know a few guys there :-) Ha, I have actually been entertaining that idea for quite some time, but it seems rather difficult to penetrate that domain as an outsider. The links you shared only seem to confirm that. :-\ I'm not sure I would even want to compete with the Google/Apple Pay duopoly, for now I'd mostly just be interested in an open-source, privacy-preserving solution for contactless payments. Anyway, you might want to add your contact info to your HN profile – just in case. ;-)
      - charcircuit 2y ago
        >What prevents a phone from emulating a regular physical credit card? If this were possible fraudsters would be easily be able to clone people's cards by getting close to them. The protocol was explicitly designed for this to not be possible. There are secrets that live on the card itself and are not exposed
        palata 2y ago
        So a phone can totally emulate a regular physical credit card, if it has the private key. Behaving like a credit card does not mean that the credit card is clonable.
- j16sdiz 2y ago
  Many NFC chip don't allow setting uid either, and none of the EMV card require cloning uid

charcircuit 2y ago

>But on Android apps have been able to use the NFC chip just fine The last time I looked at it, it was not possible because Android doesn't let apps control the uid that gets used for NFC.

codethief 2y ago
Ah right, good point. I did forget about that. Either way, even if apps had full control over the chip, my understanding is that building a wallet app would still amount to much more than just interfacing with the NFC chip.
- dzikimarian 2y ago
  You need connection to card scheme, which means you need ton of paperwork, which means you need ton of money. That's biggest issue :-) For technical side - there are companies selling complete SDKs.
  - codethief 2y ago
    Could you elaborate? You seem like you know quite a bit about this topic. While I've known that building a wallet is not as simple as configuring the NFC chip and one would have to interface with banks on the backend etc., I've failed to understand exactly why. What prevents a phone from emulating a regular physical credit card?
    - dzikimarian 2y ago
      On technical level - nothing. Thing is, that payment card is basically private key, that's derived from master key controlled by the bank. This key signs your transactions. Tokenization adds some extra steps (eg. single use keys), but it's fundamentally the same. What it means - you cannot obtain working card profile if bank doesn't issue it to you. Therefore you need blessing from bank & card scheme to be connected to this ecosystem. If you want to go deeper into this rabbit hole I can recommend two sources: * https://developer.mastercard.com/product/mdes https://developer.mastercard.com/product/mdes - Mastercards framework for tokenization * https://developer.verestro.com/books/token-requestor https://developer.verestro.com/books/token-requestor - actual solution. It focuses on offering for single issuer, because market for Google Pay competition is pretty narrow, but technically it's mostly the same + way more red tape. If you ever decide to try - ping me, I happen to know a few guys there :-)
      - codethief 1y ago
        Thank you so much! That's very enlightening! > If you ever decide to try - ping me, I happen to know a few guys there :-) Ha, I have actually been entertaining that idea for quite some time, but it seems rather difficult to penetrate that domain as an outsider. The links you shared only seem to confirm that. :-\ I'm not sure I would even want to compete with the Google/Apple Pay duopoly, for now I'd mostly just be interested in an open-source, privacy-preserving solution for contactless payments. Anyway, you might want to add your contact info to your HN profile – just in case. ;-)
    - charcircuit 2y ago
      >What prevents a phone from emulating a regular physical credit card? If this were possible fraudsters would be easily be able to clone people's cards by getting close to them. The protocol was explicitly designed for this to not be possible. There are secrets that live on the card itself and are not exposed
      - palata 2y ago
        So a phone can totally emulate a regular physical credit card, if it has the private key. Behaving like a credit card does not mean that the credit card is clonable.
j16sdiz 2y ago
Many NFC chip don't allow setting uid either, and none of the EMV card require cloning uid