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> presumably have a centralized database which maintains a record of any credit card used at a home depot That's a bit of a leap. I'd assume they just have a h
by benburton 12y ago
> presumably have a centralized database which maintains a record of any credit card used at a home depot
That's a bit of a leap. I'd assume they just have a hash of the data.
- MichaelGG 12y agoCC numbers are not that large of a space and can be enumerated. They could use a short hash (like a 26-bit hash) so each hash value has multiple plausible numbers -- at the risk of having collisions.
- btgeekboy 12y agoWhat does that get you, though? The formula for a valid card number (Mod 10) is public. If Home Depot uses a 1-way hash for the card number, and ONLY uses the card number, you gain nothing - you still need the expiration date/CVV/Name to do much else.
- MichaelGG 12y agoThat's true whether or not they use a hash function.
- thefreeman 12y agoLet's be honest here. They probably have the full details of every transaction in plain text in a database.
- otterley 12y agoIf they do, they're not PCI compliant and risk having their ability to conduct credit card transactions revoked.