Electronic Authentication Systems

• US 20140365776A1
• Filed: 06/06/2014
• Published: 12/11/2014
• Est. Priority Date: 06/06/2013
• Status: Active Grant

• Current Assignee: Mastercard International Incorporated (MasterCard Incorporated)
• Original Assignee: Mastercard International Incorporated (MasterCard Incorporated)
• Inventors: Smets, Patrik, Roberts, Dave, Garrett, Duncan, Mestr, Patrick
• Granted Patent: US 9,485,092 B2
• Time in Patent Office: Days
• US Class Current: 713/171
• CPC Class Codes: G06Q 20/102 Bill distribution or payments
• CPC Class Codes: G06Q 20/341 Active cards, i.e. cards including their own processing means, e.g. including an IC or chip
• CPC Class Codes: G06Q 20/3829 involving key management
• CPC Class Codes: G06Q 20/401 Transaction verification
• CPC Class Codes: G06Q 20/409 Device specific authentication in transaction processing
• CPC Class Codes: H04L 2209/08 Randomization, e.g. dummy operations or using noise
• CPC Class Codes: H04L 2209/16 Obfuscation or hiding, e.g. involving white box
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 63/1408 by monitoring network traffic monitoring network traffic per se H04L43/00
• CPC Class Codes: H04L 9/0841 involving Diffie-Hellman or related key agreement protocols
• CPC Class Codes: H04L 9/0869 involving random numbers or seeds
• CPC Class Codes: H04L 9/3066 involving algebraic varieties, e.g. elliptic or hyper-elliptic curves

Abstract

A transaction device for establishing a shared secret with a point of interaction (POI) over a communications network to enable encrypted communications between the transaction device and the point of interaction, the device comprising: an input arranged to receive communications from the point of interaction; a processor arranged to generate a first communication according to a Diffie-Hellman protocol; an output arranged to send the first communication to the point of interaction; wherein the processor is arranged to apply a randomly generated blinding factor, r, when generating the first communication and wherein, in response to receiving a second communication from the point of interaction at the input, the second communication having been generated according to the Diffie-Hellman protocol, the processor is arranged to apply the randomly generated blinding factor and generate a shared secret according to the Diffie-Hellman protocol in dependence on data contained within the second communication.

Claims

1. A transaction device for establishing a shared secret with a point of interaction (POI) over a communications network to enable encrypted communications between the transaction device and the point of interaction, the device comprising:

an input arranged to receive communications from the point of interaction;

a processor arranged to generate a first communication according to a Diffie-Hellman protocol;

an output arranged to send the first communication to the point of interaction;

wherein the processor is arranged to apply a randomly generated blinding factor, r, when generating the first communication; and

wherein, in response to receiving a second communication from the point of interaction at the input, the second communication having been generated according to the Diffie-Hellman protocol, the processor is arranged to apply the randomly generated blinding factor and generate a shared secret according to the Diffie-Hellman protocol in dependence on data contained within the second communication.

2. A transaction device according to claim 1, wherein the processor is arranged to use an elliptic Diffie-Hellman protocol.

3. A transaction device according to claim 1, wherein the device comprises a static public key Qc and the processor is arranged to use the public key when generating the first communication.

4. A transaction device according to claim 1, wherein the transaction device comprises a public key Qc which is the product of a private key d_c and a point G on a curve that is part of an elliptic group.

5. A transaction device according to claim 4, wherein point G is known to the transaction device and the point of interaction prior to the first communication being generated.

6. A transaction device according to claim 4, wherein the processor is arranged to calculate R=r·

Qc for inclusion in the first communication.

7. A transaction device according to claim 6, wherein the second communication comprises an ephemeral public key Q_t of the point of interaction where Q_t=d_t·

G and d_t is an ephemeral private key of the point of interaction.

8. A transaction device according to claim 7, wherein the processor is arranged to generate the shared secret by combining the public key from the second communication with private key d_c and applying the blinding factor r to generate rd_cd_t·

G.

9. A transaction device according to claim 8, wherein, in response to generating the shared secret, the processor is arranged to generate a further communication to the point of interaction, the further communication comprising the public key of the transaction device, security certificates and the blinding factor r, the further communication being encrypted in dependence with the shared secret.

10. A transaction device according to claim 8, wherein the processor is arranged to calculate key K_c wherein K_c=f(rd_c·

Q_t).

11. A transaction device according to claim 10, wherein the processor is arranged to encrypt subsequent communications with the point of interaction using key K_c.

12. A transaction device according to claim 11, wherein at the end of a communication session with the point of interaction, the processor is arranged to delete the random blinding factor r and the key K_c.

13. A transaction device according to claim 1, comprising a random number generator for generating the blinding factor r.

14. A mobile communications device comprising the transaction device according to claim 1.

15. A mobile communications device according to claim 14, wherein the mobile communications device comprises a secure element, the transaction device being located at least partially within the secure element.

16. A bank transaction card comprising the transaction device according to claim 1.

17. A method of establishing a shared secret between a transaction device and a point of interaction (POI) over a communications network to enable encrypted communications between the transaction device and the point of interaction, the method comprising:

generating, at the transaction device, a first communication according to a Diffie-Hellman protocol;

sending the first communication to the point of interaction;

wherein generating the first communication comprises applying a randomly generated blinding factor, r; and

wherein, in response to receiving a second communication from the point of interaction at the input, the second communication having been generated according to the Diffie-Hellman protocol, the method comprises applying the randomly generated blinding factor and generating a shared secret according to the Diffie-Hellman protocol in dependence on data contained within the second communication.

18-56. -56. (canceled)

57. A non-transitory computer-readable storage medium storing executable computer program instructions that, when executed by at least one processor, cause the at least one processor to:

generate a first communication according to a Diffie-Hellman protocol;

send the first communication to a point of interaction (POI) over a communications network to enable encrypted communications between a transaction device and the point of interaction; and

in response to receiving a second communication from the point of interaction at the input;

apply a randomly generated blinding factor, r; and

generate a shared secret according to the Diffie-Hellman protocol in dependence on data contained within the second communication.