Authenticated diffie-hellman key agreement protocol where the communicating parties share a secret key with a third party

• US 6,766,453 B1
• Filed: 04/28/2000
• Issued: 07/20/2004
• Est. Priority Date: 04/28/2000
• Status: Expired due to Term

• Current Assignee: Valtrus Innovations Limited (f/k/a Dolya Holdco 9 Limited) (Key Patent Innovations Limited)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Young, Albert, Nessett, Danny M., Tsai, Joe, Chen, Bofu, OʼHara, Bob
• Primary Examiner(s): Vu, Kim
• Assistant Examiner(s): TRUONG, THANHNGA B
• Application Number:
  US09/560,396
• Time in Patent Office: 1,544 Days
• Field of Search: 713/171, 713/169, 380/283, 382/100, 455/410, 455/411
• US Class Current: 713/171
• CPC Class Codes: H04L 2209/80 Wireless
• 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
• CPC Class Codes: H04L 9/3242 involving keyed hash functions, e.g. message authentication codes [MACs], CBC-MAC or HMAC

Abstract

The present invention provides a method and system for performing an authenticated Diffie-Hellman key agreement protocol over a network where the communicating parties share a secret key with a third party. In one embodiment, the network is a wireless network, wherein a wireless client electronic system (WC) and a network access point electronic system (AP) are the parties executing the authenticated Diffie-Hellman key agreement protocol. In this embodiment, the WC and the AP exchange a shared secret key for encrypting wireless communications between the wireless client electronic system and the network access point electronic system. In one embodiment, the WC shares a first secret key with a RADIUS server of the network. Similarly, the AP shares a second secret key with the RADIUS server of the network. The first and second secret keys are utilized for performing an authentication protocol.

Claims

1. A method of performing an authenticated Diffie-Hellman key agreement protocol over a network between a first communicator sharing a first secret key with an authentication resource (AR) and a second communicator sharing a second secret key with said AR, said method comprising the steps of:

a) generating a first message authentication code (MAC) of a first variable using said first secret key for said first communicator;

b) generating a second MAC of a second variable using said second secret key for said second communicator;

c) transmitting over said network to said AR said first variable, said second variable, a first identifier corresponding to said first communicator, a second identifier corresponding to said second communicator, said first MAC, and said second MAC, wherein said AR is configured for determining a secret key corresponding to an identifier transmitted over said network;

d) generating a third MAC of said first variable using said first secret key determined by said AR from said first identifier and a fourth MAC of said second variable using said second secret key determined by said AR from said second identifier;

e) if said first MAC matches said third MAC and said second MAC matches said fourth MAC, generating a fifth MAC of said second variable using said second secret key determined by said AR from said second identifier and a sixth MAC of said first variable using said first secret key determined by said AR from said first identifier;

f) transmitting over said network to said second communicator said fifth MAC, said first variable, said second variable, and said first identifier;

g) generating a seventh MAC of said second variable using said second secret key for said second communicator;

h) transmitting over said network to said first communicator said sixth MAC, said first variable, said second variable, and said second identifier;

i) generating an eighth MAC of said first variable using said first secret key for said first communicator; and

j) if said fifth MAC matches said seventh MAC and said sixth MAC matches said eighth MAC, generating a shared secret key based on said first variable for said second communicator and said shared secret key based on said second variable for said first communicator, wherein said shared secret key facilitates encrypted communication between said first communicator and said second communicator.

2. A method as recited in claim 1 wherein said first variable is generated based on a first random number generated by said first communicator.

3. A method as recited in claim 1 wherein said second variable is generated based on a second random number generated by said second communicator.

4. A method as recited in claim 1 wherein said first variable and said second variable are generated based on modular arithmetic.

5. A method as recited in claim 1 wherein said first variable and said second variable are generated based on elliptic curve cryptography.

6. A method as recited in claim 1 wherein said first MAC, said second MAC, said third MAC, said fourth MAC, said fifth MAC, said sixth MAC, said seventh MAC, and said eighth MAC are generated based on a one-way hash function.

7. A method as recited in claim 1 wherein said first MAC is generated based on a concatenation comprising said first identifier and said first variable.

8. A method as recited in claim 1 wherein said second MAC is generated based on a concatenation comprising said second identifier and said second variable.

9. A method as recited in claim 1 wherein said third MAC is generated based on a concatenation comprising said first identifier and said first variable.

10. A method as recited in claim 1 wherein said fourth MAC is generated based on a concatenation comprising said second identifier and said second variable.

11. A method as recited in claim 1 wherein said fifth MAC is generated based on a concatenation comprising said first identifier, said first variable, and said second variable.

12. A method as recited in claim 11 wherein step f) further comprises transmitting over said network to said second communicator a first designator for identifying a designation associated with said first communicator such that the second communicator can determine whether to communicate with said first communicator.

13. A method as recited in claim 12 wherein said fifth MAC is generated based on said concatenation further comprising said first designator.

14. A method as recited in claim 13 wherein said seventh MAC is generated based on a second concatenation comprising said first identifier, said first designator, said first variable, and said second variable.

15. A method as recited in claim 1 wherein said sixth MAC is generated based on a concatenation comprising said second identifier, said first variable, and said second variable.

16. A method as recited in claim 15 wherein step h) further comprises transmitting over said network to said first communicator a second designator for identifying a designation associated with said second communicator such that the first communicator can determine whether to communicate with said second communicator.

17. A method as recited in claim 16 wherein said sixth MAC is generated based on said concatenation further comprising said second designator.

18. A method as recited in claim 17 wherein said eighth MAC is generated based on a second concatenation comprising said second identifier, said second designator, said first variable, and said second variable.

19. A method as recited in claim 1 wherein said seventh MAC is generated based on a concatenation comprising said first identifier, said first variable, and said second variable.

20. A method as recited in claim 1 wherein said eighth MAC is generated based on a concatenation comprising said second identifier, said first variable, and said second variable.

21. A method as recited in claim 1 wherein said network is a wireless network.

22. A method as recited in claim 1 wherein said first communicator comprises a wireless client electronic system.

23. A method as recited in claim 22 wherein said first identifier corresponds to said wireless client electronic system.

24. A method as recited in claim 1 wherein said second communicator comprises a wireless network access point electronic system.

25. A method as recited in claim 24 wherein said second identifier corresponds to said wireless network access point electronic system.

26. A method as recited in claim 1 wherein said authentication resource comprises a RADIUS server.

27. A method as recited in claim 1 wherein said authentication resource comprises a RADIUS server and a backend server coupled to said RADIUS server.

28. A network comprising:

an authentication resource (AR);

a network access point electronic system (AP) coupled to said AR; and

a client electronic system (client) coupled to said AP via a connection, wherein said AR shares a first secret key with said client and shares a second secret key with said AP,

wherein said client is configured to generate a first message authentication code (MAC) of a first variable using said first secret key,

wherein said client is configured to transmit via said AP to said AR said first variable, said first MAC, and a first identifier corresponding to said client,

wherein said AP is configured to generate a second MAC of a second variable using said second secret key,

wherein said AP is configured to transmit to said AR said second variable, said second MAC, and a second identifier corresponding to said AP,

wherein said AR is configured to determine a secret key corresponding to an identifier transmitted over said network, is configured to generate a third MAC of said first variable using said first secret key determined from said first identifier, and is configured to generate a fourth MAC of said second variable using said second secret key determined from said second identifier,

wherein said AR is configured to generate a fifth MAC of said second variable using said second secret key and is configured to generate a sixth MAC of said first variable using said first secret key if said first MAC matches said third MAC and said second MAC matches said fourth MAC,

wherein said AR is configured to transmit to said AP said fifth MAC, said first variable, said second variable, and said first identifier,

wherein said AR is configured to transmit via said AP to said client said sixth MAC, said first variable, said second variable, and said second identifier,

wherein said AP is configured to generate a seventh MAC of said second variable using said second secret key and is configured to generate a shared secret key based on said first variable if said fifth MAC matches said seventh MAC,

wherein said shared secret key facilitates encrypted communication between said AP and said client, and

wherein said client is configured to generate an eighth MAC of said first variable using said first secret key and is configured to generate said shared secret key based on said second variable if said sixth MAC matches said eighth MAC.

29. A network as recited in claim 28 wherein said first variable is generated based on a first random number generated by said client electronic system.

30. A network as recited in claim 28 wherein said second variable is generated based on a second random number generated by said network access point electronic system.

31. A network as recited in claim 28 wherein said first variable and said second variable are generated based on modular arithmetic.

32. A network as recited in claim 28 wherein said first variable and said second variable are generated based on elliptic curve cryptography.

33. A network as recited in claim 28 wherein said first MAC, said second MAC, said third MAC, said fourth MAC, said fifth MAC, said sixth MAC, said seventh MAC, and said eighth MAC are generated based on a one-way hash function.

34. A network as recited in claim 28 wherein said first MAC is generated based on a concatenation comprising said first identifier and said first variable.

35. A network as recited in claim 28 wherein said second MAC is generated based on a concatenation comprising said second identifier and said second variable.

36. A network as recited in claim 28 wherein said third MAC is generated based on a concatenation comprising said first identifier and said first variable.

37. A network as recited in claim 28 wherein said fourth MAC is generated based on a concatenation comprising said second identifier and said second variable.

38. A network as recited in claim 28 wherein said fifth MAC is generated based on a concatenation comprising said first identifier, said first variable, and said second variable.

39. A network as recited in claim 38 wherein said authentication resource is configured to transmit to said network access point electronic system a first designator for identifying a designation associated with said client electronic system such that the network access point electronic system can determine whether to communicate with said client electronic system.

40. A network as recited in claim 39 wherein said fifth MAC is generated based on said concatenation further comprising said first designator.

41. A network as recited in claim 40 wherein said seventh MAC is generated based on a second concatenation comprising said first identifier, said first designator, said first variable, and said second variable.

42. A network as recited in claim 28 wherein said sixth MAC is generated based on a concatenation comprising said second identifier, said first variable, and said second variable.

43. A network as recited in claim 42 wherein said authentication resource is configured to transmit via said network access point electronic system to said client electronic system a second designator for identifying a designation associated with said network access point electronic system such that the client electronic system can determine whether to communicate with said network access point electronic system.

44. A network as recited in claim 43 wherein said sixth MAC is generated based on said concatenation further comprising said second designator.

45. A network as recited in claim 44 wherein said eighth MAC is generated based on a second concatenation comprising said second identifier, said second designator, said first variable, and said second variable.

46. A network as recited in claim 28 wherein said seventh MAC is generated based on a concatenation comprising said first identifier, said first variable, and said second variable.

47. A network as recited in claim 28 wherein said eighth MAC is generated based on a concatenation comprising said second identifier, said first variable, and said second variable.

48. A network as recited in claim 28 wherein said network is a wireless network.

49. A network as recited in claim 28 wherein said client electronic system comprises a wireless client electronic system.

50. A network as recited in claim 49 wherein said first identifier corresponds to said wireless client electronic system.

51. A network as recited in claim 28 wherein said network access point electronic system comprises a wireless network access point electronic system.

52. A network as recited in claim 51 wherein said second identifier corresponds to said wireless network access point electronic system.

53. A network as recited in claim 28 wherein said authentication resource comprises a RADIUS server.

54. A network as recited in claim 28 wherein said authentication resource comprises a RADIUS server and a backend server coupled to said RADIUS server.

55. A network as recited in claim 28 wherein said connection is a wireless connection.