System and method for generating collision-free identifiers for financial transaction cards

• US 20050242171A1
• Filed: 01/24/2005
• Published: 11/03/2005
• Est. Priority Date: 01/23/2004
• Status: Active Grant

• Current Assignee: Mastercard International Incorporated (MasterCard Incorporated)
• Original Assignee: Mastercard International Incorporated (MasterCard Incorporated)
• Inventors: Smets, Patrik, Vanneste, Paul
• Granted Patent: US 7,299,974 B2
• Time in Patent Office: Days
• US Class Current: 235/380
• CPC Class Codes: G06Q 30/02 Marketing; Price estimation or determination; Fundraising
• CPC Class Codes: G06Q 30/0241 Advertisements

Abstract

A one-way permutation over financial transaction card data provides a merchant with a unique card identifier for each financial transaction card that is used by a customer to purchase goods from a merchant. This card identifier, which is not the actual financial transaction card data, may then be permissibly stored by the merchant and used to uniquely identify the customer'"'"'s financial transaction card, and may also be used to determine the frequency with which that customer makes purchases using that card.

Claims

1. A method for tracking customer purchasing behavior, comprising:

receiving financial transaction card data stored on the customer'"'"'s financial transaction card;

encrypting the financial transaction card data using a one-way permutation function to derive a unique card identifier;

storing the unique card identifier; and

associating each purchase made using the customer'"'"'s financial transaction card with the unique card identifier.

2. The method of claim 1 wherein the financial transaction card data includes the primary account number of the financial transaction card.

3. The method of claim 2 wherein the financial transaction card data further includes the cardholder'"'"'s name and the expiration date of the financial transaction card.

4. The method of claim 1 wherein the one-way permutation function is based on the factorization of large integers.

5. The method of claim 1 wherein the one-way permutation function is based on discrete logarithms in integer groups.

6. The method of claim 1 wherein the one-way permutation function is based on discrete logarithms over elliptic curve groups.

7. The method of claim 1 wherein the unique card identifier is stored on the financial transaction card when the financial transaction card is first personalized for the customer.

8. The method of claim 1 wherein the unique card identifier is generated by the financial transaction card reader.

9. The method of claim 8 wherein the financial transaction card reader is a smart card reader.

10. The method of claim 1 wherein the unique card identifier is generated by the merchant back-office system.

11. The method of claim 1 further comprising associating a name of the customer with the card identifier.

12. A system for tracking customer purchase behavior, comprising:

a financial transaction card reader that receives financial transaction card data stored on the customer'"'"'s financial transaction card;

an encryption module that encrypts the financial transaction card data using a one-way permutation function to derive a unique card identifier;

a data storage module that stores the unique card identifier and further stores data associating each purchase made using the customer'"'"'s financial transaction card with the unique card identifier.

13. The system of claim 12 wherein the financial transaction card data includes the primary account number of the financial transaction card.

14. The system of claim 13 wherein the financial transaction card data further includes the cardholder'"'"'s name and the expiration date of the financial transaction card.

15. The system of claim 12 wherein the one-way permutation function is based on the factorization of large integers.

16. The system of claim 12 wherein the one-way permutation function is based on discrete logarithms in integer groups.

17. The system of claim 12 wherein the one-way permutation function is based on discrete logarithms over elliptic curve groups.

18. The system of claim 12 wherein the unique card identifier is stored on the financial transaction card when the financial transaction card is first personalized for the customer.

19. The system of claim 12 wherein the unique card identifier is generated by the financial transaction card reader.

20. The system of claim 12 wherein the financial transaction card reader is a smart card reader.

21. The system of claim 12 wherein the unique card identifier is generated by the merchant back-office system.

22. The system of claim 12 wherein the data storage module further associates a name of the customer with the card identifier.