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A card fingerprint can be used to seamlessly identify card numbers stored in your vault without the burden of PCI compliance. Key features of card fingerprints.
  • Secure and irreversible fingerprint generation for every card received by the system
  • Inclusion of fingerprint values in API responses wherever payment methods are returned, ensuring seamless integration with your system

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Use-cases

There are a few use cases for card fingerprints.
  1. Identifying fraud: Because the API does not return the original raw card number back via the API, it’s hard to know if a card has been used previously in a fraudulent transaction. For example, two transactions with the same masked card number of 4111 11** **** 1111 could be the same number or two different numbers.
  2. Identifying duplicate cards: Similarly, you could use the card fingerprint to determine if the same card is stored twice for a user without needing to see the original number.

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How fingerprints are generated

Gr4vy generates a fingerprint as a keyed hash of the card number, using a secret key that Gr4vy holds. Because the key is never shared, you can’t compute a fingerprint yourself, and you can’t compare it with a fingerprint or hash from a payment service or another system. Compare fingerprints only with other fingerprints that Gr4vy returns. A card fingerprint identifies a card number. It isn’t the device fingerprint that’s sent to anti-fraud services. For that, see anti-fraud device fingerprinting.

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Availability & limitations

A card fingerprint is returned for every payment_method returned by the API. Fingerprints are the same for every unique card number used. Because of this, payments made with Apple Pay, Click to Pay, and some Google Pay have a different fingerprint than cards filled in by hand by your customers.

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Comparison to PAR

PAR and fingerprints go hand in hand to detect duplicate and fraudulent cards.
  • PAR has limited availability and depends on the data received back from the payment service, while card fingerprints are available for every card transaction
  • A PAR represents the underlying account, while a fingerprint represents the actual card number. As a result, the fingerprint is different when using a digital wallet like Apple Pay or Google Pay.