MULTI-PARTY KEY AGREEMENT METHOD USING BILINEAR MAP AND SYSTEM THEREFOR

• US 20090154711A1
• Filed: 07/25/2008
• Published: 06/18/2009
• Est. Priority Date: 12/18/2007
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: LEE, Byunggil, KIM, Myunghwan, HONG, Dowon, JHO, Namsu
• Granted Patent: US 8,447,036 B2
• Time in Patent Office: Days
• US Class Current: 380/286
• CPC Class Codes: H04L 9/083 involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]
• CPC Class Codes: H04L 9/3073 involving pairings, e.g. identity based encryption [IBE], bilinear mappings or bilinear pairings, e.g. Weil or Tate pairing

Abstract

The present invention provides an efficient method and system in which a plurality of participants share a secret key in a communication environment that is not ensured. According to an embodiment of the invention, each of the participants is assigned with a secret key from a key generation party, generates exchange information, and transmits its own exchange information to the other participant to exchange the exchange information with each other. Each of the participants generates a shared key on the basis of the exchange information and its own secret key.

Claims

1. A multi-party key agreement method in which a plurality of participants share a key, the method comprising:

allowing each of the participants to be assigned with a secret key from a key generation party;

allowing each of the participants to generate exchange information;

allowing each of the participants to transmit its own exchange information to the other participants, such that the exchange information is exchanged between the participants; and

allowing each of the participants to generate a shared key on the basis of the received exchange information and its own secret key.

2. The multi-party key agreement method of claim 1,

wherein the exchange information is generated on the basis of values that are generated from groups where bilinear maps are defined and that are opened by the key generation party.

3. The multi-party key agreement method of claim 2,

wherein, in the generating of the shared key, each of the participants calculates a bilinear map of the received exchange information and its own secret key and generates the shared key.

4. The multi-party key agreement method of claim 1, further comprising:

after the exchanging of the exchange information,

verifying the other participants by calculating a bilinear map, using the exchange information transmitted from the other participants.

5. The multi-party key agreement method of claim 1,

wherein the secret key is generated on the basis of values that are generated from groups where bilinear maps are defined and that are opened by the key generation party.

6. The multi-party key agreement method of claim 5,

wherein the secret key is generated further on the basis of an identifier of each participant, each identifier being opened to other participants.

7. The multi-party key agreement method of claim 1,

wherein the key generation party does not participate in key agreement processes after assigning the secret key.

8. The multi-party key agreement method of claim 7,

wherein the key agreement processes are completed in one round.

9. A multi-party key agreement system including a key generation party and a plurality of participants,

wherein the key generation party assigns a secret key to each of the participants, and

each of the participants generates exchange information and transmits the exchange information to the other participants, such that the exchange information is exchanged between the participants, and generates a shared key on the basis of the exchange information received from the other participants and its own secret key.

10. The multi-party key agreement system of claim 9,

wherein the exchange information is generated on the basis of values that are generated from groups where bilinear maps are defined and that are opened by the key generation party.

11. The multi-party key agreement system of claim 10,

wherein each of the participants calculates a bilinear map of the received exchange information and its own secret key and generates the shared key.

12. The multi-party key agreement system of claim 9,

wherein each of the participants uses the exchange information transmitted from the other participants to calculate a bilinear map and verifies the other participants.

13. The multi-party key agreement method of claim 9,

wherein the secret key is generated on the basis of values that are generated from groups where bilinear maps are defined and that are opened by the key generation party.

14. The multi-party key agreement method of claim 13,

wherein the secret key is generated further on the basis of an identifier of each participant, each identifier being opened to other participants.

15. The multi-party key agreement method of claim 9,

wherein the key generation party does not participate in key agreement processes after assigning the secret key.

16. The multi-party key agreement method of claim 15,

wherein the key agreement processes are completed in one round.