Roaming encryption key rekeying apparatus and method

• US 20060233371A1
• Filed: 04/03/2006
• Published: 10/19/2006
• Est. Priority Date: 04/14/2005
• Status: Abandoned Application

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola Solutions, Inc.
• Inventors: Sowa, Hans C., Kruegel, Chris A., Senese, Thomas J., Bright, Michael W., Woodward, Timothy G.
• Application Number:
  US11/396,722
• Publication Number:
  US 20060233371A1
• Time in Patent Office: Days
• US Class Current: 380/248
• CPC Class Codes: H04L 2209/80 Wireless
• CPC Class Codes: H04L 9/0822 using key encryption key
• 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 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying
• CPC Class Codes: H04W 12/041 Key generation or derivation

Abstract

Roaming encryption key rekeying apparatus and method comprising a first system key management facility that communicates to a communication unit roaming information is disclosed. The roaming information is encrypted using a first encryption scheme that is decipherable by the communication unit. Further, the first system key management facility communicates to a second system key management facility the roaming information. In this communication, the roaming information is encrypted as a function of a second encryption scheme that is decipherable by the second system key management facility.

Claims

1. A method comprising:

at a first system key management facility;

communicating to a communication unit roaming information, wherein at least a portion of the roaming information is encrypted using a first encryption scheme that is decipherable by the communication unit; and

communicating to a second system key management facility the roaming information, wherein at least a portion of the roaming information is encrypted as a function of a second encryption scheme that is decipherable by the second system key management facility.

2. The method of claim 1 wherein the roaming information comprises a roaming encryption key.

3. The method of claim 2 wherein the roaming encryption key is at least one of a roaming key encryption key and a roaming traffic key encryption key.

4. The method of claim 2 wherein the communication unit utilizes the roaming encryption key for rekeying with the second system key management facility.

5. The method of claim 1 wherein the first encryption scheme is at least one of a unique key encryption key and a traffic key encryption key.

6. The method of claim 1 further comprising:

at the second system key management facility;

communicating to the communicating unit a rekeying message wherein the rekeying message is encrypted with an encryption scheme associated with the roaming information.

7. The method of claim 6 wherein the rekeying message further comprises an encryption key for use with the second system key management facility.

8. The method of claim 1 wherein the step of communicating to a communication unit roaming information further comprises the step of communicating at least one of a) wirelessly and b) via a wired connection to the first system key management facility.

9. The method of claim 1 further comprising the step of acknowledging in response the steps of communicating.

10. The method of claim 1 wherein the second encryption scheme is at least one of a shared key encryption key, a shared traffic key encryption key, public key protocol, an industry standard secure protocol, and manual means.

11. The method of claim 1 further comprising:

at the second system key management facility;

receiving a rekey request from a communication unit within coverage of the second system key management facility;

forwarding the rekey request to the first system key management facility;

receiving the roaming information from the first system key management facility, wherein at least a portion of the roaming information is encrypted as a function of a second encryption scheme that is decipherable by the second system key management facility;

forwarding a response from the first system key management facility wherein the response comprises roaming information for the communication unit; and

communicating to the communication unit a rekeying message wherein the rekeying message is encrypted with an encryption scheme associated with the roaming information.

12. The method of claim 11 further comprising receiving an acknowledgement message from the communication unit to indicate successful reception of the roaming information.

13. The method of claim 11 wherein the second encryption scheme is at least one of a shared key encryption key and a shared traffic encryption key.

14. A method for rekeying communication units, comprising:

at a communication unit, wherein the communication unit is in communication with a second key management facility;

receiving a message comprising an encrypted key for use with the second system key management facility wherein at least a portion of the message is encrypted using a roaming encryption key that is decipherable by the communication unit,

wherein the roaming encryption key is for rekeying with the second system key management facility.

15. The method of claim 14 wherein the roaming encryption key is at least one of a roaming key encryption key and a roaming traffic key encryption key.

16. The method of claim 14 wherein the encrypted key is a visiting traffic encryption key.

17. The method of claim 14 further comprising the steps of:

receiving the roaming encryption key from a first system key management facility before receiving the message,

wherein the first system key management facility sends the roaming encryption key to the communication unit.

18. The method of claim 17 wherein the first system key management facility sends the roaming encryption key in at least one of four ways comprising a) directly to the communication unit, b) over the air to the communication unit, c) via a second system key management facility where the second system key management facility serves as a proxy for forwarding to the communication unit, and d) via a second system base site where the second system base site communicates directly with the first system key management facility.

19. The method of claim 17 further comprising the step of sending a rekey request to the second system key management facility requesting the roaming encryption key before receiving the message.

20. A key management facility comprising:

at least one roaming encryption key;

a roaming encryption key selector comprising a roaming encryption key output;

a roaming request processor that is operably coupled to the roaming encryption key selector;

a wireless communication interface that is operably coupled to the at least one roaming encryption key and the roaming encryption request processor; and

wherein the wireless communication interface further couples to a wireless communications system that supports wireless encrypted communications amongst authorized communication units using the at least one roaming encryption key.