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Okay, so let's imagine for a moment that the "secure, encrypted" database of card numbers has also been compromised. The attacker would have the plaintext name

Okay, so let's imagine for a moment that the "secure, encrypted" database of card numbers has also been compromised. The attacker would have the plaintext name and address, and an encrypted 16 digit number, with an entropy of at most 53 bits - maybe 66 bits if the expiry date is included. That's before you take card number check digits and geographically-likely prefix codes into account, which will reduce the entropy. (Edit: yes, they wouldn't store the CVV). And don't get me started on showing the user the last four digits of the card number. It wouldn't take much effort in this day and age for the attacker to try all possible card numbers, and then they have name, address, and card number. Game over, man. Wouldn't it be possible for them instead to store a token generated from the card number and Ebay/Paypal's incoming bank account number, which can only be used for paying into that particular account?

mikeash 12y ago
But what does it matter if they figure out your card number? You're not liable for fraudulent transactions. It's pretty easy to get a new card number. Your issuer takes a hit, but whatever, not my problem. Checking account info is much, much worse. It's much harder to reverse fraudulent transactions there, and much harder to get a new number.
- mnw21cam 12y ago
  It can still be very inconvenient.
  - mikeash 12y ago
    It really shouldn't be. I had a card compromised in the Target breach and they sent me a new one without my intervention. I've had fraudulent charges made before, and it's been trivial to get it fixed. I've never had a checking account compromise, but I'm pretty sure it would be a massive pain in the ass by comparison.
    - schrodinger 12y ago
      Mentioned above, but relevant here too. I've had my debit card compromised several times, and it was still trivial - one phone call and was refunded in a few days.
      - mikeash 12y ago
        Debit cards mostly give you the same protections as credit cards. They're worse in that the money comes out of your account immediately (but is supposed to be returned when you report fraud), and the rules are different and less favorable if your PIN is also compromised, but overall it's not too bad. A compromise of your routing and account number for your checking account is potentially much worse. It's harder to take advantage of, but it's also much harder to fix. (I'm not sure if you were treating the debit card as analogous to credit cards or account numbers, so treat this as confirmation/correction/elaboration/whatever as appropriate.)
    - oneeyedpigeon 12y ago
      Did the bank charge you for the replacement cards? Is there any real reason not to just regularly - say every 3 months - request a new card for peace of mind?
      - mikeash 12y ago
        They did not. That stuff is basically a loss leader for them. From what I recall with the Target incident, their cost is something like $2-5 for each replacement card, so it's not entirely trivial. If you requested a new one on a regular basis for no good reason, they might put a stop to it one way or another. As far as peace of mind goes, since the consequences are so mild, I wouldn't worry about it.
      - zevyoura 12y ago
        The biggest obstacle is that it's an annoyance to update the number for any recurring charges you have set up.
    - rblatz 12y ago
deleted 12y ago
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mikeash 12y ago

But what does it matter if they figure out your card number? You're not liable for fraudulent transactions. It's pretty easy to get a new card number. Your issuer takes a hit, but whatever, not my problem. Checking account info is much, much worse. It's much harder to reverse fraudulent transactions there, and much harder to get a new number.

mnw21cam 12y ago
It can still be very inconvenient.
- mikeash 12y ago
  It really shouldn't be. I had a card compromised in the Target breach and they sent me a new one without my intervention. I've had fraudulent charges made before, and it's been trivial to get it fixed. I've never had a checking account compromise, but I'm pretty sure it would be a massive pain in the ass by comparison.
  - schrodinger 12y ago
    Mentioned above, but relevant here too. I've had my debit card compromised several times, and it was still trivial - one phone call and was refunded in a few days.
    - mikeash 12y ago
      Debit cards mostly give you the same protections as credit cards. They're worse in that the money comes out of your account immediately (but is supposed to be returned when you report fraud), and the rules are different and less favorable if your PIN is also compromised, but overall it's not too bad. A compromise of your routing and account number for your checking account is potentially much worse. It's harder to take advantage of, but it's also much harder to fix. (I'm not sure if you were treating the debit card as analogous to credit cards or account numbers, so treat this as confirmation/correction/elaboration/whatever as appropriate.)
  - oneeyedpigeon 12y ago
    Did the bank charge you for the replacement cards? Is there any real reason not to just regularly - say every 3 months - request a new card for peace of mind?
    - mikeash 12y ago
      They did not. That stuff is basically a loss leader for them. From what I recall with the Target incident, their cost is something like $2-5 for each replacement card, so it's not entirely trivial. If you requested a new one on a regular basis for no good reason, they might put a stop to it one way or another. As far as peace of mind goes, since the consequences are so mild, I wouldn't worry about it.
    - zevyoura 12y ago
      The biggest obstacle is that it's an annoyance to update the number for any recurring charges you have set up.
  - rblatz 12y ago

deleted 12y ago

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