Biometric identification method and device adapted to verification on chip cards
View Patent ↗A method and associated device for checking a biometric signature by a simple and secure calculation adapted to personal objects of the chip card type. The method is based on the storage within the object of an obscured biometric signature and an associated authentication code. A terminal capturing a fingerprint compares the fingerprint data with the obscured biometric signature transmitted by the card and transfers the result of this comparison to the chip card, which validates this result with the authentication code.
1. An enrolment method comprising the steps of:
capturing biometric data;
extracting a true biometric signature composed of true particular biometric data from the captured biometric data;
producing false particular biometric data;
generating an obscured biometric signature by combining the false particular biometric data with the true particular biometric data; and
producing an authentication code which indicates which data are the false and true particular biometric data of the obscured biometric signature.
2. An enrolment method according to claim 1 , wherein the false particular biometric data are produced in a manner consistent with the true particular biometric data.
3. An enrolment method according to claim 2 , wherein at least one false particular biometric data item is produced by transforming a true biometric data item.
4. An enrolment method according to claim 3 , wherein the true particular biometric data are minutiae which correspond to fingerprint data of a first finger and said at least one false minutiae is produced from minutiae of a second finger.
5. An enrolment method according to claim 3 , wherein at least one false particular biometric data item is produced by detecting a true biometric data item and transforming the true biometric data item in order to create the false particular biometric data item.
6. An enrolment method according to claim 1 , wherein the authentication code is established according to the following steps:
ordering the true and false particular biometric data of the obscured biometric signature; and
generating a series of bits, with a length equal to the total number of true and false particular biometric data of the obscured biometric signature, with each bit indicating respectively whether a corresponding ordered particular biometric data item is true or false.
7. An enrolment method according to claim 1 , wherein the biometric data are those of a fingerprint and the particular biometric data are minutiae.
8. An enrolment method according to claim 1 , wherein the obscured biometric signature and the authentication code are recorded on a secure memory of a chip card.
9. A biometric identity check method comprising the steps of:
capturing biometric data;
extracting a true biometric signature composed of true particular biometric data from the captured biometric data;
comparing the true biometric signature with an obscured biometric signature composed of true particular biometric data and false particular biometric data;
producing a code indicating which data of the obscured biometric signature are the true and false biometric data on the basis of the comparison with the true biometric signature; and
comparing said produced code with an authentication code indicating which data are the true and false particular biometric data of the obscured biometric signature.
10. A biometric identity check method according to claim 9 , wherein the authentication code is stored in a secure memory of a personal object and the comparison of the produced code and authentication code takes place within the personal object.
11. A biometric identity check method according to claim 10 for accessing a service by means of a service terminal, based on a chip card storing the authentication code and the obscured biometric signature, comprising the following steps:
transferring the obscured biometric signature from the chip card to the service terminal for the comparison of the true biometric signature with the obscured biometric signature and producing the code within the service term; and
transferring the produced code from the service terminal to the chip card for comparison of the code with the authentication code on the chip card.
12. An enrolment device, comprising: biometric signature extraction means for obtaining a true biometric signature composed of true particular biometric data from captured biometric data; and
obscuring means for producing false particular biometric data, combining said false particular biometric data with said true particular biometric data to obtain an obscured biometric signature, and producing an authentication code for indicating which data are the true and false particular biometric data of the obscured biometric signature.
13. An enrolment device according to claim 12 , further comprising a device for communicating with a chip card to transfer the obscured biometric signature and the authentication code to the chip card.
14. A personal object comprising:
a secure memory that contains an obscured biometric signature composed of true particular biometric data and false particular biometric data and an authentication code that indicates which data are the true and false particular biometric data of the obscured biometric signature;
communication means to transfer the obscured biometric signature to a service terminal; and
a means for comparing a code, produced by the service terminal and transferred by the communication means to the personal object, with the authentication code, wherein the produced code indicates which data are the true and false particular biometric data of the obscured biometric signature on the basis of a true biometric signature obtained by the service terminal.
15. A personal object according to claim 14 , wherein said object is a chip card.
16. A service terminal comprising:
extraction means for obtaining a true biometric signature composed of true particular biometric data from captured biometric data; and
means for producing a code from a comparison between the true biometric signature and an obscured biometric signature composed of true particular biometric data and false particular biometric data, said produced code indicating which data are the true and false biometric data of the obscured biometric signature on the basis of the true biometric signature obtained by the service terminal.
17. A service terminal according to claim 16 , further comprising a communication device for communicating with a personal object to transfer the obscured biometric signature from the personal object to the service terminal and to transfer the produced code to the personal object.