Method and Device for Agreeing Shared Key Between First Communication Device and Second Communication Device

• US 20090041251A1
• Filed: 01/26/2007
• Published: 02/12/2009
• Est. Priority Date: 01/30/2006
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Rajasekaran, Hariharan, Abendroth, Jörg, Cuellar, Jorge
• Granted Patent: US 8,261,076 B2
• Time in Patent Office: Days
• US Class Current: 380/277
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 2463/101 applying security measures for digital rights management
• CPC Class Codes: H04L 63/061 for key exchange, e.g. in peer-to-peer networks cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 63/0869 for achieving mutual authentication cryptographic mechanisms or cryptographic arrangements for mutual authentication H04L9/3273
• CPC Class Codes: H04L 9/0844 with user authentication or key authentication, e.g. ElGamal, MTI, MQV-Menezes-Qu-Vanstone protocol or Diffie-Hellman protocols using implicitly-certified keys

Abstract

Based on security parameters previously agreed upon by first and second communication devices, a first security value is determined by the second communication device and transmitted to the first communication device. The first communication device determines second and third security values based on the security parameters and the first security value and transmits the second and third security values to the second communication device. The second communication device determines a fourth security value based on the security parameters and, if the second security value matches the fourth security value, authenticates the first communication device. Upon successful authentication of the first communication device, a shared key is determined by both communication devices based on the third security value and the security parameters.

Claims

1-7. -7. (canceled)

8. A method for agreeing upon a shared key between first communication and second communication devices, comprising:

agreeing upon security parameters by the first and second communication devices;

determining a first security value by the second communication device based on the security parameters previously agreed upon;

transmitting the first security value from the second communication device to the first communication device;

determining second and third security values by the first communication device based on the first security value and the security parameters previously agreed upon;

transmitting the second and third security values from the first communication device to the second communication device;

authenticating the first communication device by the second communication device, if the second security value matches a fourth security value determined by the second communication device based on the security parameters previously agreed upon;

determining, by the first and second communication devices upon successful authentication of the first communication device, a shared key based on the third security value and the security parameters previously agreed upon.

9. The method as claimed in claim 8, wherein the security parameters previously agreed upon include parameters of an elliptic curve and parameters for an asymmetric cryptographic method.

10. The method as claimed in claim 8, wherein the security parameters previously agreed upon and the first, second and third security values are transmitted wirelessly between the first and the second communication devices.

11. The method as claimed in claim 8, wherein the security parameters previously agreed upon and the first, second and third security values are transmitted between the first and the second communication devices via high-frequency electromagnetic signals in accordance with an RFID standard.

12. The method as claimed in claim 8,

further comprising incrementing a counter value in the first communication device after each agreement of the shared key,

wherein said determining of the third security value is based on the counter value.

14. A device for agreeing upon a shared key between first and second communication devices, comprising:

means for agreeing upon security parameters by the first and second communication devices;

means, in the second communication device, for determining a first security value based on the security parameters previously agreed upon and for transmitting the first security value to the first communication device;

means, in the first communication device, for determining second and third security values based on the first security value and the security parameters previously agreed upon and for transmitting the second and third security values to the second communication device;

means, in the second communication device, for determining a fourth security value based on the security parameters previously agreed upon and for authenticating the first communication device, if the second security value matches the fourth security value;

means for determining, by the first and second communication devices upon successful authentication of the first communication device, a shared key based on the third security value and the security parameters previously agreed upon.