Authentication of documents having magnetic stripe

• US 8,104,677 B2
• Filed: 11/21/2008
• Issued: 01/31/2012
• Est. Priority Date: 11/21/2008
• Status: Active Grant

• Current Assignee: Visa International Service Association (Visa, Inc.)
• Original Assignee: Visa International Service Association (Visa, Inc.)
• Inventors: Faith, Patrick, Fang, Xiang, Kato, Craig, Hammad, Ayman, Koganti, Krishna (Kris) Prasad
• Primary Examiner(s): Hess, Daniel
• Assistant Examiner(s): Kelly, Rafferty
• Application Number:
  US12/276,224
• Publication Number:
  US 20100127072A1
• Time in Patent Office: 1,166 Days
• Field of Search: 235/380, 235/449
• US Class Current: 235/380
• CPC Class Codes: G06K 7/087 flux-sensitive, e.g. magnetic, detectors G06K7/10336 takes precedence

Abstract

Methods, systems, and apparatus for efficiently authenticating a document (e.g. a credit card) having a magnetic stripe are provided. The magnetic field at different points of the magnetic stripe are measured, e.g., by a checkout scanner to create a magnetic signature. Digital samples of the measurements may be transformed into coefficients of continuous basis functions, e.g., a Fourier transform. These coefficients are then compared to reference values (e.g. corresponding coefficients) to produce a measure of the authenticity of the document. The number of coefficients used can advantageously be smaller than the number of digital samples without compromising accuracy, thus using less bandwidth between a scanner and an authentication entity.

Claims

1. A method for authenticating a document that includes a magnetic stripe having a distinct magnetic characteristic, wherein the magnetic characteristic exists over one or more predetermined segments of the magnetic stripe, the method comprising:

receiving, at an authentication device, a set of expansion coefficients corresponding to a set of continuous basis functions, wherein the expansion coefficients are based on digital samples of an analog signal representative of the magnetic characteristic;

comparing the received expansion coefficients to reference expansion coefficients; and

based on the comparison, providing a measure of an authenticity of the document.

2. The method of claim 1, further comprising:

calculating new reference expansion coefficients using the received expansion coefficients.

3. The method of claim 2, wherein calculating new reference expansion coefficients involves using an optimization algorithm.

4. The method of claim 3, wherein the optimization algorithm minimizes a total error resulting from comparing a plurality of sets of received expansion coefficients to the new reference expansion coefficients or maximizes the measure of authenticity for a plurality of sets of received expansion coefficients compared to the new reference expansion coefficients.

5. The method of claim 3, wherein the optimization algorithm uses an artificial neural network.

6. The method of claim 1, wherein comparing the calculated expansion coefficients to reference expansion coefficients includes:

taking a difference between each of the received expansion coefficients and a corresponding one of the reference expansion coefficients.

7. The method of claim 6, wherein providing a measure of the authenticity of the document includes:

calculating a sum of the differences between the received expansion coefficients and the reference expansion coefficients.

8. The method of claim 1, further comprising:

comparing the measure to at least one threshold value to determine a categorization of the document.

9. The method of claim 8, wherein the categorization is selected from a group including:

the document is not authentic; and

the document is authentic.

10. The method of claim 8, further comprising:

using the measure to determine a distribution of measures associated with the authentic document; and

updating the threshold value using the distribution.

11. The method of claim 10, further comprising receiving one or more additional sets of expansion coefficients, wherein the threshold is updated after a change of the distribution of measures reaches a predetermined level.

12. The method of claim 1, further comprising:

using the measure of authenticity to determine a risk level for a transaction involving an account associated with the document.

13. The method of claim 12, wherein the set of expansion coefficients are received as part of a request for authorizing the transaction.

14. The method of claim 1, wherein the one or more predetermined segments of the magnetic stripe are located between consecutive pieces of data written to the magnetic stripe.

15. The method of claim 1, wherein a sum of the set of expansion coefficients multiplied by respective continuous basis functions approximates the analog signal representative of the magnetic characteristic.

16. A computer program product comprising a computer readable medium encoded with a plurality of instructions for controlling a computing system to perform a method for authenticating a document that includes a magnetic stripe having a distinct magnetic characteristic, wherein the magnetic characteristic occurs over one or more predetermined segments of the magnetic stripe, the instructions comprising:

receiving a set of expansion coefficients corresponding to a set of continuous basis functions, wherein the expansion coefficients are based on digital samples of an analog signal representative of the magnetic characteristic;

comparing the received expansion coefficients to reference expansion coefficients; and

based on the comparison, providing a measure of an authenticity of the document.

17. The computer program product of claim 16, wherein the instructions further comprise:

calculating new reference expansion coefficients using the received reference coefficients.

18. A system for authenticating a document that includes a magnetic stripe having a distinct magnetic characteristic, wherein the magnetic characteristic occurs over one or more predetermined segments of the magnetic stripe, the system comprising:

an input for receiving a set of expansion coefficients corresponding to a set of continuous basis functions, wherein the expansion coefficients are based on digital samples of an analog signal representative of the magnetic characteristic;

a processor communicably coupled with the input, the processor configured to;

compare the received expansion coefficients to reference expansion coefficients; and

based on the comparison, provide a measure of an authenticity of the document.

19. The system of claim 18, wherein the processor is further configured to calculate new reference expansion coefficients using the received reference coefficients.

20. The system of claim 18, wherein the processor is further configured to use the measure of authenticity to determine a risk level for a transaction involving an account associated with the document.

21. The system of claim 20, wherein the set of expansion coefficients are received as part of a request for authorizing the transaction.

22. The system of claim 18, wherein the processor is further configured to compare the measure to at least one threshold value to determine a categorization of the document.