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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" me

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.
  - viraptor 10y ago
    Stopping things from working is the whole point of revokation. Parallel, offline, "emergency" CAs would work, that's true. But it would still take some time to move everyone over to a new configuration.
    - Dylan16807 10y ago
      To make a card break, you have to revoke the card or revoke [nearly] every CA that card trusts. If you're revoking a card, you did that on purpose; that's not a flaw. And it's exceedingly unlikely that every CA would be revoked. I don't understand the scenario where revocations break the system. We've never had to revoke the majority of web certificates in a single five year period.

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.
- viraptor 10y ago
  Stopping things from working is the whole point of revokation. Parallel, offline, "emergency" CAs would work, that's true. But it would still take some time to move everyone over to a new configuration.
  - Dylan16807 10y ago
    To make a card break, you have to revoke the card or revoke [nearly] every CA that card trusts. If you're revoking a card, you did that on purpose; that's not a flaw. And it's exceedingly unlikely that every CA would be revoked. I don't understand the scenario where revocations break the system. We've never had to revoke the majority of web certificates in a single five year period.