METHOD OF SHARING A SESSION KEY BETWEEN WIRELESS COMMUNICATION TERMINALS USING A VARIABLE-LENGTH AUTHENTICATION CODE

• US 20130332739A1
• Filed: 04/06/2012
• Published: 12/12/2013
• Est. Priority Date: 04/26/2011
• Status: Active Grant

• Current Assignee: Soongsil University Research Consortium Techno-Park
• Original Assignee: Soongsil University Research Consortium Techno-Park
• Inventors: Yi, Jeong Hyun, Ma, Gun-Il, Lee, Hyeong Chan
• Granted Patent: US 9,078,126 B2
• Time in Patent Office: Days
• US Class Current: 713/171
• CPC Class Codes: H04L 2209/80 Wireless
• CPC Class Codes: H04L 9/0841 involving Diffie-Hellman or related key agreement protocols
• CPC Class Codes: H04W 12/041 Key generation or derivation
• CPC Class Codes: H04W 12/0471 Key exchange
• CPC Class Codes: H04W 12/65 Environment-dependent, e.g. using captured environmental data

Abstract

Disclosure relates to a method of sharing a session key between wireless communication terminals using a variable-length authentication code. The method includes: generating a public key by using an own private key; generating a message including the public key and a first random number and encoding the message using an own secret key to exchange an encrypted message with the other terminal; decoding the encrypted message of the other terminal by receiving a secret key of the other terminal; generating an authentication code by calculating the first random number and a second random number included in the decoded message; obtaining a medium value from the authenticated code; and generating a session key by using a public key included in the decoded message of the other terminal.

Claims

1. A method of sharing a session key between wireless communication terminals based on a Diffie-Hellman (DH) protocol, the method comprising:

generating a public key by using an own private key;

generating a message including the public key and a first random number and encoding the message using an own secret key to exchange an encrypted message with the other terminal;

decoding the encrypted message of the other terminal by receiving a secret key of the other terminal;

generating an authentication code by calculating the first random number and a second random number included in the decoded message;

obtaining a medium value from the authenticated code; and

generating a session key by using a public key included in the decoded message of the other terminal.

2. The method of claim 1, wherein the message further comprises an identifier and a reflection attack verification value.

3. The method of claim 2, further comprising checking a reflection attack verification value of the other terminal included in the decoded message.

4. The method of claim 3, wherein the secret key is a disposable key, and the first and second random numbers are comprised of bit streams having a value of 0 or 1.

5. The method of claim 4, wherein the generating of the authentication code comprises generating an authentication code by performing an exclusive OR operation on the first random number and the second random number.

6. The method of claim 5, wherein the authentication code is divided into n bits (where n is a natural number of 2 or more), and

the divided authentication code corresponds to one grid, and

each grid is indicated by one color.

7. The method of claim 6, wherein the obtaining of the medium value from the authentication code comprises:

dividing the authentication code into 2 or more bits and inputting the divided authentication code to an out-of-band (OOB) function to obtain the medium value; and

displaying the medium value on a screen including a plurality of grids.

8. The method of claim 7, wherein the number S′

of grids required to display the medium value is obtained by the following equation;

9. The method of claim 6, wherein the obtaining of the medium value from the authentication code comprises:

inputting the authentication code to an OOB function to obtain the medium value; and

controlling a plurality of light emitting diodes (LEDs) to turn on or off according to the medium value.

10. The method of claim 6, wherein the obtaining of the medium value from the authentication code comprises:

inputting the authentication code to an OOB function to obtain the medium value; and

playing a stored sound source file according to the medium value.

11. A wireless communication terminal for sharing a session key with the other terminal based on a Diffie-Hellman (DH) protocol, the wireless communication terminal comprising:

a storage unit comprising a public key generated by using an own private key;

an encoding unit generating a message including the public key and a first random number and encoding the message using an own secret key to exchange an encrypted message with the other terminal;

a decoding unit decoding the encrypted message of the other terminal by receiving a secret key of the other terminal;

an authentication code generating unit generating an authentication code by calculating the first random number and a second random number included in the decoded message;

an out-of-band (OOB) converting unit obtaining a medium value from the authenticated code; and

a session key generating unit generating a session key by using a public key included in the decoded message of the other terminal.

12. The wireless communication terminal of claim 11, wherein the message further comprises an identifier and a reflection attack verification value.

13. The wireless communication terminal of claim 12, wherein the decoding unit checks a reflection attack verification value of the other terminal included in the decoded message.

14. The wireless communication terminal of claim 13, wherein the secret key is a disposable key, and the first and second random numbers are comprised of bit streams having a value of 0 or 1.

15. The wireless communication terminal of claim 14, wherein the authentication code generating unit generates an authentication code by performing an exclusive OR operation on the first random number and the second random number.

16. The wireless communication terminal of claim 15, wherein the authentication code is divided into n bits (where n is a natural number of 2 or more), and

the divided authentication code corresponds to one grid, and

each grid is indicated by one color.

17. The wireless communication terminal of claim 16, wherein the OOB converting unit obtains the medium value from the authentication code divided into 2 or more bits and inputted to the OOB converting unit and displays the medium on a screen including a plurality of grids.

18. The wireless communication terminal of claim 16, wherein the number S′

of grids required to display the medium value is obtained by the following equation;