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Comment by MikeKusold | Hacker News Reader

Paying with your phone is actually more secure than the old mag-swipe method. Your phone will tokenize your credit card information, which makes it significantly harder to track credit card usage across various merchants.

Of course it isn't as private as cash, but it is a step forward from mag-swipe.

Square has a good explainer if you want to read more: https://squareup.com/us/en/townsquare/what-does-tokenization...

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Harder for whom? The attack vector here isn't "hackers compromised everyone and can correlate your data", it's "Visa knows everything about you".

I agree with the GP, this is a huge privacy blind spot.

> The attack vector here isn't

There are multiple attack vectors. One of them is "why did I just get another charge from that place we visited last June". Another being "oops, we plugged our pin into a skimmer", etc.

Agree that letting Visa/MC/whomever know everything about your transactions is a choice...

Otoh if they pay you 3ish % for it, you might decide you're more than happy to.

I have half a mind to make a debit card that lets you whitelist merchants. You use the same card everywhere, but unless the merchant is in the whitelist, the charge fails. Also, you can set limits and rules.

Basically like privacy.com, but why use a new card per merchant?

hackers need not apply. I'm sure retailers will happily sell your transaction data to a third party aggregator, and that transaction data is more fine grained than what Visa gets to know about you (spending at Walmart vs specifically buying diapers).

So now Apple gets to know what Visa knows. Still, for the time being, they don't seem to know individual items. And many here seem to think Apple is more trustworthy than random anonymous data broker.

> secure than the old mag-swipe

Though at least in the EU the mag-swipe method was phased out and replaced with a chip based method years ago. (A chip with secure module, requiring PIN if you pay for more then a small amount, or otherwise unusual.)

And as far as I know that method is still more secure then Apple pay and similar.

Apple Pay only tokenizes card information once when the card is added to the Apple Wallet on a device, not for every transaction. This means that usage for an on-device tokenized card can still be tracked until the card is removed and re-added.

I believe while the token is generated once, each transaction is signed with a unique signature (I believe that's the term) that only the payment processor can decipher. The merchant doesn't get any stable/identifiable information that can be used to track you across purchases/sessions/stores.

No, the merchant still does get a stable identifier with every payment (the "device account number").

More recently, an additional identifier uniquely identifying the underlying card has also been added [1]. That one persists even across multiple devices and token deletions.

[1] https://www.level2kernel.com/payment_account_reference.html

Interesting! I stand corrected. Thanks.

A signature doesn't hide information, it only tells you that it hasn't been modified. All the information that's being signed is by definition already in the payload given to the merchant.

If it's actually encrypting information (not just signing it), then that's another thing entirely, but signatures don't hide data.

Good point about a signature not hiding the data. I got my terminology mixed up. I thought it was encoding it in a way so that only the payment processor could see.

But that's not necessarily the case either, as somebody else brought up the fact that identifiers ARE in fact passed to the merchant.

I think you can also tap a button in the Wallet app that lets you generate a new token

Are you possibly mixing this up with the Apple Card "request new card number" feature? In general, creating a new token requires deleting and re-adding a card.

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