Method and apparatus for applying and verifying a biometric-based digital signature to an electronic document

• US 6,553,494 B1
• Filed: 07/21/1999
• Issued: 04/22/2003
• Est. Priority Date: 07/21/1999
• Status: Expired due to Term

• Current Assignee: Sensar, Inc. (Advent International Corporation)
• Original Assignee: Sensar, Inc. (Advent International Corporation)
• Inventors: Glass, Randal
• Primary Examiner(s): DARROW, JUSTIN T
• Application Number:
  US09/358,593
• Time in Patent Office: 1,371 Days
• Field of Search: 713/176, 713/185, 713/186
• US Class Current: 713/186
• CPC Class Codes: G06F 21/32 using biometric data, e.g. fingerprints, iris scans or voiceprints
• CPC Class Codes: G06F 21/64 Protecting data integrity, e.g. using checksums, certificates or signatures
• 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 9/3247 involving digital signatures

Abstract

A method and apparatus are disclosed whereby a person signs an electronic document using a personal biometric. A sample of biometric data is collected from the person at the time of the signing of the document, and encrypted with the document itself and various other data to form a digital signature. The encryption technique utilized irrefutably couples the biometric data with the document. To authenticate the coupling, an authenticator signature is generated using the original data and is then compared with the original signature to verify a match there between. The biometric data used to generate the authenticator signature is then matched with a sample provided by an alleged signer of the document to verify his or her identity.

Claims

1. A method of generating a digital signature for an electronic document comprising the steps of:

a. applying a first hashing function to an electronic document to produce a hash value;

b. acquiring biometric data from a plurality of signers of said electronic document;

c. applying a second hashing function to the combination of the hash value of the electronic document and the acquired biometric data;

d. generating a digital signature related to a first signer of said electronic document utilizing as input biometric data related to said first signer, the previous hash value of step c and a secret key; and

e. generating digital signatures for subsequent signers of said electronic document utilizing as input the signature of a previous signer, biometric data related to the signer whose signature is being generated, and a secret key.

2. The method of claim 1 in which the digital signature is generated by an encrypting function having as input the hash output of step c and a secret key.

3. The method of claim 2 wherein the encrypting function is asymmetric.

4. The method of claim 1 further comprising the step of generating or acquiring a unique token and wherein said first hashing function is applied to a combination of said unique token and said electronic document.

5. The method of claim 4 wherein the token is associated with a time or date, or transaction identifier.

6. The method of claim 4 wherein said unique token and said electronic document are combined by concatenation.

7. The method of claim 1 wherein said biometric data is a biometric template derived from a larger set of biometric information.

8. The method of claim 1 where said key uniquely identified an input device from which said biometric data was acquired.

9. The method of claim 1 wherein said biometric data represents an image of the iris of one eye of a signer of said electronic document.

10. The method of claim 1 wherein said biometric data represents an image of iris of both eyes of a signer of said electronic documents.

11. The method of claim 1 wherein said digital signature and said biometric data are concatenated to form a biometric document signature certificate.

12. The method of claim 11 wherein said biometric document signature certificate also includes a unique token, said hash value and said key.

13. The method of claim 12 further comprising the step of sending said biometric document signature certificate to a central server, where it may be retrieved for authentication purposes.

14. The method of claim 13 further comprising the step of receiving a receipt code for retrieving said certificate from said central server at a later time.

15. The method of claim 13 further comprising the step of applying with the central server a digital signature to the certificate.

16. A method of using a digital signature of a previous signer to authenticate the association of an electronic document and a subsequent signer of said electronic document comprising the steps of:

a. retrieving biometric data of the previous signer originally associated with said electronic document; and

b. verifying the association between said biometric data of the previous signer and said electronic document by recomputing the digital signature of the previous signer, thereby authenticating the association of the electronic document and the subsequent signer.

17. The method of claim 16 further comprising the step of comparing said biometric data associated with said electronic document with a known sample from an alleged signer of said electronic document.

18. A method of using a digital signature of a previous signer to authenticate the association of an electronic document and a subsequent signer'"'"'s biometric data comprising the steps of:

a. acquiring a key;

b. using said key to decrypt said digital signature of the subsequent signer;

c. retrieving original biometric data related to the previous signer of said electronic document;

d. applying a hashing function to said electronic document to produce a hash value;

e. generating a second hash value having as input said biometric data of the subsequent signer, and said hash value of step d; and

f. comparing a result of step b with result of step e to verify that they match, thereby authenticating the association of the electronic document with the subsequent signer'"'"'s biometric data.

19. The method of claim 18 further comprising the step of retrieving a transaction token, said token having been used in the generation of said digital signature, wherein said hashing function of step d is applied to a combination of said token and said electronic document.

20. The method of claim 19 wherein said token and said electronic document are combined by concatenation.

21. The method of claim 18 wherein said digital signature was created with an encrypting function which is asymmetric and wherein said key is the public complement of a private key used to encrypt said digital signature.

22. The method of claim 18 wherein said biometric data is a biometric template derived form a larger set of biometric information.

23. The method of claim 18 further comprising the step of comparing said biometric data to a known sample from a signer of said electronic document to verify the identity of the signer.

24. An apparatus for generating a digital signature of a previous signer of an electronic document to authenticate the association of the electronic document and a subsequent signer of said electronic document, comprising:

a. an input device for collecting biometric data of the previous signer, said input device having a secret key comprised of a data value;

b. an encoder, for applying a hash function to a combination of said electronic document and a unique token to produce a hash value; and

c. a signature generator, coupled to said input device and said encoder, for generating said digital signature of the previous signer based on said biometric data, said hash value and said key, the digital signature of the previous signer being used to authenticate the association of the electronic document and the subsequent signer.

25. The apparatus of claim 24 wherein said input device is capable of converting said biometric data into a biometric template, and wherein said biometric template is thereafter used in place of said biometric data.

26. The apparatus of claim 24 wherein said input device is a video camera.

27. The apparatus of claim 26 further comprising a tamper-proof enclosure in which said video camera is located.

28. The apparatus of claim 27 wherein said camera is rendered non-functional if an attempt to gain access to said camera enclosure is detected.

29. The apparatus of claim 24 wherein said biometric data represents a scan of the iris of one or both eyes of the signer of said electronic document.

30. The apparatus of claim 24 wherein said unique token also serves as a timestamp.

31. The apparatus of claim 24 wherein said unique token is retrieved from a token generator.

32. The apparatus of claim 31 wherein said token generator is accessible via a network.

33. The apparatus of claim 24 wherein said key uniquely identifies said input device.

34. The apparatus of claim 24 wherein said unique token and said electronic document are combined by concatenation.