Biometric authentication

1. A method for enrolling a user of an electronic device comprising:

a biometry sensor for acquiring sensing signals representative of a biometric feature;

a processor for computing an enrollment representation based on said sensing signals;

a secure processor isolated from said processor for computing an encrypted representation of said enrollment representation, wherein said method comprises:

acquiring sensing signals representative of a candidate's biometric feature;

based on said sensing signals, determining an enrollment representation by said processor;

determining, by said secure processor, an encrypted representation of said enrollment representation;

when said encrypted representation has been determined, discarding said enrollment representation from said secure processor;

storing, in said secure processor, said encrypted representation;

when said encrypted representation has been established, providing a success signal indicative of successful encryption to said processor,

in response to receiving the success signal, storing, by the processor, the enrollment representation.

2. The method according to claim 1 , further comprising:

signing, by the secure processor, said encrypted representation with a private key unique to said electronic device.

3. The method according to claim 1 , wherein determining said encrypted representation comprises determining a hash representation of said enrollment representation.

4. The method according to claim 1 , comprising:

sending the encrypted representation to the processor, wherein the processor stores the encrypted representation as part of an enrollment template for future verification.

5. The method according to claim 1 , wherein said biometry sensor is a fingerprint sensor and said biometric feature is a fingerprint pattern.

6. The method according to claim 1 , wherein said processor is operable in a trusted execution environment.

7. A method for authenticating a user of an electronic device comprising:

a biometry sensor for acquiring sensing signals representative of a biometric feature;

a processor for computing a verification representation based on said sensing signals; and,

a secure processor isolated from said processor for computing an encrypted representation of said enrollment representation, wherein said method comprises:

acquiring sensing signals representative of a candidate's biometric feature;

determining, by said processor, a verification representation based on said sensing signals;

comparing, said verification representation with at least one stored enrollment representation;

sending, when a match is found between said verification representation and a stored enrollment representation, said enrollment representation and said verification representation to said secure processor;

determining, by said secure processor, an encrypted representation of said enrollment representation and comparing said encrypted representation with at least one stored encrypted representation;

when a match is found between said encrypted representation and a stored encrypted representation, comparing, by said secure processor, said verification representation with said enrollment representation, and, when said verification representation matches said enrollment representation, providing a pass signal indicative of successful authentication.

8. The method according to claim 7 , wherein determining an encrypted representation comprises determining a hash representation of said enrollment representation or said verification representation.

9. The method according to claim 7 , wherein said biometry sensor is a fingerprint sensor and said biometric feature is a fingerprint pattern.

10. The method according to claim 7 , wherein said processor is operable in a trusted execution environment.

11. An electronic device, comprising:

a biometry sensor for acquiring sensing signals representative of a biometric feature;

a processor configured to compute a verification representation and an enrollment representations based on sensing signals acquired by said biometry sensor,

a secure processor configured to:

determine encrypted representations of at least said enrollment representation, and

store an encrypted enrollment representation for future authentication, wherein for enrolling a user of said electronic device:

said processor is configured to determine said enrollment representation,

said secure processor is configured to determine and store said encrypted representation of said enrollment representation, and when said encrypted representation has been determined, discard said enrollment representation from said secure processor, wherein

when said encrypted representation of said enrollment representation is established, said secure processor is configured to send a success signal to said processor, wherein

in response to receiving the success signal the processor is configured to store the enrollment representation for future authentication.

12. An electronic device, comprising:

a biometry sensor for acquiring sensing signals representative of a biometric feature;

a processor configured to compute a verification representation and an enrollment representations based on sensing signals acquired by said biometry sensor,

a secure processor configured to:

determine encrypted representations of at least said enrollment representation, and

store an encrypted enrollment representation for future authentication,

wherein for authenticating a user of said electronic device:

said processor is configured to:

determine said verification representation;

compare said verification representation with at least one stored enrollment representation, and

send, when a match is found between said verification representation and a stored enrollment representation, said enrollment representation and said verification representation to said secure processor;

wherein said secure processor is configured to:

determine an encrypted representation of said enrollment representation and compare said encrypted representation with at least one stored encrypted representation, and

when a match is found between said encrypted representation and a stored encrypted representation, compare said verification representation with said enrollment representation, and provide a pass signal indicative of successful authentication when said verification representation matches said enrollment representation.

13. The electronic device according to claim 11 , wherein said secure processor comprises a secure control unit and secure storage unit.

14. The electronic device according to claim 12 , wherein said encrypted representations are hash representations.

15. The electronic device according to claim 12 , wherein the electronic device is a mobile phone, a smart card, or a smart watch.

16. The electronic device according to claim 12 , wherein said processor is operable in a trusted execution environment.

17. The electronic device according to claim 12 , wherein said secure processor comprises a secure control unit and secure storage unit.