Revocable biometrics with robust distance metrics

• US 7,773,784 B2
• Filed: 10/14/2005
• Issued: 08/10/2010
• Est. Priority Date: 10/15/2004
• Status: Active Grant

• Current Assignee: HID Global Corporation (Assa Abloy AB)
• Original Assignee: The Board of Regents of the University of Colorado (University of Colorado System)
• Inventors: Boult, Terrance Edward
• Primary Examiner(s): Strege; John B
• Application Number:
  US11/665,524
• Publication Number:
  US 20090022374A1
• Time in Patent Office: 1,761 Days
• Field of Search: 382/115, 382/124, 380/277, 713/186
• US Class Current: 382/124
• CPC Class Codes: G06F 18/22 Matching criteria, e.g. proximity measures
• CPC Class Codes: G06V 10/761 Proximity, similarity or dissimilarity measures
• CPC Class Codes: G06V 40/10 Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 9/3231 Biological data, e.g. fingerprint, voice or retina network architectures or network communication protocols for supporting authentication of entities using biometrical features in a packet data network H04L63/0861
• CPC Class Codes: H04L 9/3234 involving additional secure or trusted devices, e.g. TPM, smartcard, USB or software token network architectures or network communication protocols for supporting authentication of entities using an additional device in a packet data network H04L63/0853

Abstract

Techniques, systems and methods relating to cryptographically secure revocable biometric signatures and identification computed with robust distance metrics are described. Various biometric cryptographically secure revocable transformation approaches are described that support a robust pseudo-distance computation in encoded form, thereby supporting confidence in verification, and which can provide for verification without identification.

Claims

1. A method for secure revocable identity tokens, comprising the steps of:

a) capturing a biometric signature having a plurality of feature vectors;

b) transforming each of the plurality of feature vectors into a stable portion and a residual part

c) cryptographically encoding the stable portion to form a secured part and simply transforming the residual portion to be the residual part.

2. The method of claim 1, wherein step (b) further includes the step of:

b1) transforming at least one of the plurality of feature vectors and dividing it into a most significant bits portion and a least significant bits portion;

b2) securing the most significant bits portion.

3. The method of claim 1, wherein step (c) includes the step of using a public key encryption to produce at least part of the secured part.

4. The method of claim 1, where it is computationally intractable to recover the original feature vectors from any combination of the secured and the residual part.

5. The method of claim 2, wherein step (b2) includes the step of including a password as part of the process of generating the secured part.

6. The method of claim 5, wherein the password is not stored in a computer readable medium after completion of step (b2).

7. The method of claim 1, further including the steps of:

c) comparing the secured part of the one of the plurality of feature vectors to an associated secured part of a stored feature vector;

d) when a closeness measure of the secured parts is within a predetermined threshold, comparing a residual part of the one of the plurality of feature vectors to an associated residual part of the stored feature vector.

8. The method of claim 7, further including the step of:

e) repeating the comparing steps for all of the plurality of feature vectors to form a closeness score.

9. The method of claim 8, wherein the closeness score is essentially equal to a standard closeness score of the biometric signature.

10. A method for secure revocable identity tokens, comprising the steps of:

a) receiving a biometric signature having a plurality of feature vectors;

b) transforming each of the plurality of feature vectors and splitting each into a probe secured part and a probe residual part; and

c) comparing the probe secured part of one of the plurality of feature vector to a gallery secured part of an associated gallery feature vector.

11. The method of claim 10, further including the step of:

d) when the probe secured part and the gallery secured part are not equal, assigning a threshold closeness measure.

12. The method of claim 11, further including the steps of:

e) when the probe secured part and the gallery secured part are equal, measuring a closeness of the residual part to a gallery residual part to form a closeness measure;

f) when the closeness measure is greater than the threshold closeness measure, assigning the threshold closeness measure.

13. The method of claim 12, further including the step of:

g) when the closeness measure is not greater than the threshold closeness measure, using the closeness measure.

14. The method of claim 10, wherein step (b) further includes the step of:

b1) encrypting the probe secured part using a public key encryption.

15. The method of claim 10, wherein step (b) further includes the step of:

b1) password protecting the probe secured part.

16. A method for secure revocable identification, comprising the steps of:

a) receiving a probe biometric signature having a plurality of probe feature vectors;

b) transforming each of the plurality of probe vectors into a secured part and a residual part to form a probe identity token; and

c) determining a closeness measure between the probe identity token and a gallery identity token.

17. The method of claim 16, wherein the step (b) further includes the step of public key encrypting the secured part.

18. The method of claim 17, wherein step (c) further includes the step of:

c1) receiving a password.

19. The method of claim 17, wherein step (c) further includes the step of:

c1) comparing the secured part to a gallery secured part;

c2) when the secured part and the gallery secured part are not equal, assigning a threshold closeness measure.

20. The method of claim 19, further including the step of:

c3) when the secured part and the gallery secured part are equal, measuring a closeness of the residual part to a gallery residual part;

c4) when the closeness measure is greater than the threshold closeness measure, assigning the threshold closeness measure;

c5) when the closeness measure is not greater than the threshold closeness measure, using the closeness measure.

21. A secure revocable identification method, comprising the steps of:

a) creating a first identity token having a secure part form a biometric signature; and

b) creating a second identity token derived from the first identity token without use of the biometric signature, wherein the second identity token is not identical to the first identity token and a transformation from the first identity token increases a potential space associated with the second identity token.