Method and system for deriving an encryption key using joint randomness not shared by others

• US 8,280,046 B2
• Filed: 12/23/2005
• Issued: 10/02/2012
• Est. Priority Date: 09/12/2005
• Status: Expired due to Fees

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Rudolf, Marian, Mukherjee, Rajat Pritam
• Primary Examiner(s): Zee, Edward
• Assistant Examiner(s): Paliwal, Yogesh
• Application Number:
  US11/318,381
• Publication Number:
  US 20070058808A1
• Time in Patent Office: 2,475 Days
• Field of Search: 380/44
• US Class Current: 380/44
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 2463/061 applying further key derivation, e.g. deriving traffic keys from a pair-wise master key cryptographic mechanisms or cryptographic arrangements for generation of secret information including derivation or calculation of cryptographic keys or passwords H04L9/0861
• CPC Class Codes: H04L 63/065 for group communications cryptographic mechanisms or cryptographic arrangements for key management involving conference or group key H04L9/0833
• CPC Class Codes: H04L 63/0892 by using authentication-authorization-accounting [AAA] servers or protocols
• CPC Class Codes: H04L 9/0841 involving Diffie-Hellman or related key agreement protocols
• CPC Class Codes: H04L 9/0875 based on channel impulse response [CIR]
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying
• CPC Class Codes: H04L 9/12 Transmitting and receiving encryption devices synchronised or initially set up in a particular manner
• CPC Class Codes: H04W 12/06 Authentication
• CPC Class Codes: H04W 12/50 Secure pairing of devices
• CPC Class Codes: H04W 12/79 Radio fingerprint

Abstract

The present invention is related to a method and system for deriving an encryption key using joint randomness not shared by others (JRNSO). Communicating entities generate JRNSO bits from a channel impulse response (CIR) estimate and the JRNSO bits are used in generation of an encryption key. The authentication type may be IEEE 802.1x or a pre-shared key system. In an IEEE 802.1x system, a master key, a pairwise master key or a pairwise transient key may be generated using the JRNSO bits. The encryption key may be generated by using a Diffie-Hellman key derivation algorithm.

Claims

1. A method for deriving an encryption key for securing wireless communications the method comprising:

a wireless transmit/receive unit (WRTU) obtaining an association to an access point (AP);

the WTRU determining a secret that complies with a supported authentication;

the WTRU generating a channel impulse response (CIR) estimate based upon a signal received from the AP;

the WTRU correcting errors in the CIR estimate and generating parity bits by performing error correction coding on the CIR estimate;

the WTRU multiplexing the parity bits with a synchronization code to generate a multiplexed bit stream;

the WTRU transmitting the multiplexed bit stream to the AP;

the WTRU generating joint-randomness-not-shared-with-others (JRNSO) bits from the corrected CIR estimate;

the WTRU deriving a pairwise master key (PMK) using the secret and the JRNSO bits; and

the WTRU deriving a pairwise transient key (PTK) using the PMK and the JRNSO bits.

2. The method of claim 1, further comprising:

receiving a group key from the AP, wherein the group key is derived from one of the PMK and the PTK.

3. The method of claim 1, wherein the determining a secret includes:

on a condition that the supported authentication type is not based on a pre-shared key (PSK), authenticating with an authentication server and reporting the secret to the authentication server; and

on a condition that the supported authentication type is based on a PSK, setting the PSK as one of the secret, the master key, and the PMK.

4. The method of claim 3, further comprising receiving a group key from the AP, wherein the group key is derived from one of the PMK and the PTK.

5. The method of claim 1, further comprising generating other JRNSO bits for updating an encryption key, whereby a new encryption key is generated by using the new JRNSO bits and the encryption key is one of the secret, the master key, the PMK, and the PTK.

6. The method of claim 1, further comprising reporting a portion of an encryption key to the AP to confirm the encryption key, wherein the encryption key is one of the secret, the master key, the PMK, and the PTK.

7. The method of claim 1 wherein the determining the secret includes determining a second pairwise master key (PMK) by:

on a condition that the supported authentication type is not a pre-shared key (PSK) type;

authenticating with an authentication server,

reporting a master secret to the authentication server, and

deriving the second PMK from the master secret;

on a condition that the supported authentication type is PSK, using a pre-shared key (PSK) as the second PMK; and

using the second PMK as the secret.

8. The method of claim 7, further comprising

receiving a group key from the AP, wherein the group key is derived from one of the second PMK and the PTK.

9. A wireless transmit/receive unit (WTRU) for deriving an encryption key for securing wireless communications, the system WTRU comprising:

a memory electronically coupled to a processor;

a transceiver electronically coupled to the processor;

the processor configured to;

report a secret to an authentication server;

generate a channel impulse response (CIR) estimate of a communication received from an access point (AP);

correct errors in the CIR estimate and generate parity bits by performing error correction coding on the CIR estimate;

multiplex the parity bits with a synchronization code to generate a multiplexed bit stream;

instruct the transceiver to transmit the multiplexed bit stream to the AP;

generate joint-randomness-not-shared-with-others (JRNSO) bits from the corrected CIR estimate;

derive a pairwise master key (PMK) using the secret and the JRNSO bits; and

derive a pairwise transient key (PTK) using the PMK and the JRNSO bits.

10. The WTRU of claim 9, wherein the WTRU is configured receive a group key from the AP, wherein the group key is derived from one of the PMK and the PTK.

11. The WTRU of claim 9, wherein the WTRU is configured to authenticate using IEEE 802.1x authentication.

12. The WTRU of claim 9, wherein the WTRU is configured to authenticate using pre-shared key (PSK) authentication, and to use a PSK as the secret.

13. The WTRU of claim 9, wherein the WTRU is configured to report a portion of the encryption key to the AP to confirm the encryption key.

14. A wireless transmit/receive unit (WTRU) for deriving an encryption key for securing wireless communications, the WTRU comprising:

a memory operatively connected to a processor;

a transceiver electronically coupled to the processor;

the processor configured to;

report a master secret to an authentication server;

generate a channel impulse response (CIR) estimate of a communication received from an access point (AP);

correct errors in the CIR estimate and generate parity bits by performing error correction coding on the CIR estimate;

multiplex the parity bits with a synchronization code to generate multiplexed bit stream;

instruct the transceiver to transmit the multiplexed bit stream to the AP;

generate joint-randomness-not-shared-with-others (JRNSO) bits from the corrected CIR estimate;

derive a pairwise master key (PMK) using the master secret and the JRNSO bits; and

derive a pairwise transient key (PTK) using the PMK and the JRNSO bits.

15. The WTRU of claim 14, wherein the WTRU is configured to receive a group key from the AP, wherein the group key is derived from one of the PMK and the PTK.

16. The WTRU of claim 14, wherein the WTRU is configured to authenticate using IEEE 802.1x authentication.

17. The WTRU of claim 14, wherein the WTRU is configured to authenticate using pre-shared key (PSK) authentication, whereby the PSK is set to one of the secret, the master key, and the PMK.

18. A wireless transmit/receive unit (WTRU) for deriving an encryption key for securing wireless communications, the WTRU comprising:

a memory operatively connected to a processor;

a transceiver operatively coupled to the processor;

the processor configured to;

report a pre-master secret to an authentication server;

generate a channel impulse response (CIR) estimate of a communication received from an access point (AP);

correct errors in the CIR estimate and generate parity bits by performing error correction coding on the CIR estimate;

multiplex the parity bits with a synchronization code to generate a multiplexed bit stream;

instruct the transceiver to transmit the multiplexed bit stream to the AP;

generate joint-randomness-not-shared-with others (JRNSO) bits from the corrected estimate;

derive a master key from the pre-master secret and the JRNSO bits;

derive a pairwise master key (PMK) using the master key and the JRNSO bits; and

derive a pairwise transient key (PTK) using the PMK and the JRNSO bits.

19. The WTRU of claim 18, wherein the WTRU is configured to receive a group key from the AP, wherein the group key is derived from one of the PMK and the PTK.