Methods and Apparatuses Generating a Radio Base Station Key in a Cellular Radio System

• US 20150065092A1
• Filed: 11/06/2014
• Published: 03/05/2015
• Est. Priority Date: 12/11/2007
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Blom, Rolf, Stattin, Magnus, Norrman, Karl
• Granted Patent: US 9,294,916 B2
• Time in Patent Office: Days
• US Class Current: 455/411
• CPC Class Codes: H04J 11/0069 Cell search, i.e. determining cell identity [cell-ID] design of multiplexing codes H04J13/00; processing access restriction or access information H04W48/16; discovery of network devices for network data management H04W8/005; sounding signals for channel estimation H04L25/0226; structure of reference signals in multicarrier modulation systems H04L27/2613; frame, time or carrier synchronisation in multicarrier modulation systems H04L27/2655
• 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 9/0656 Pseudorandom key sequence combined element-for-element with data sequence, e.g. one-time-pad [OTP] or Vernam's cipher
• CPC Class Codes: H04W 12/04 Key management, e.g. using generic bootstrapping architecture [GBA]
• CPC Class Codes: H04W 12/0431 Key distribution or pre-distribution; Key agreement
• CPC Class Codes: H04W 12/71 Hardware identity
• CPC Class Codes: H04W 12/73 Access point logical identity
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A Terminal Identity Token is created for identifying a User Equipment (UE) connected to a radio base station in a radio system. The UE communicates with the radio base station via a secure communication associated with an existing cryptographic key. The Terminal Identity Token is created based on a physical cell identity of a target cell known to both the UE and the radio base station, the terminal identity, and the existing key. By using the Terminal Identity Token, a secure communication can be established and enhanced without having to provide for additional security network components or additional signaling.

Claims

1. A method of creating a Terminal Identity Token for identifying a User Equipment (UE) connected to a radio base station in a radio system, wherein the UE communicates with the radio base station via a secure communication associated with an existing cryptographic key, said method comprising:

creating the Terminal Identity Token based on a physical cell identity of a target cell known to both the UE and the radio base station, the terminal identity and the existing key.

2. The method according to claim 1, further comprising using additional input parameters as input data when creating the Terminal Identity Token.

3. The method according to any claim 1, further comprising creating the Terminal Identity Token using a Pseudo Random Function.

4. The method according to claim 1, wherein the method is performed in the UE.

5. The method according to claim 4, further comprising transmitting the Terminal Identity Token to one of the radio base stations of the radio system as an identity of the UE.

6. The method according to claim 5, further comprising generating the Terminal Identity Token as a Pseudo Random Function using the terminal identity and the existing key and additional parameters as input.

7. The method according to claim 1, wherein the method is performed in the radio base station acting as a source radio base station.

8. The method according to claim 7, further comprising distributing the Terminal Identity Token to a number of target radio base stations of the radio system.

9. A method in a radio base station acting as a target base station of identifying a User Equipment (UE) wherein the UE communicates with a source radio base station via a secure communication associated with an existing cryptographic key, said method comprising:

receiving a first Terminal Identity Token from a source base station, the first Terminal Identity Token being generated by the source base station based on a physical cell identity of a target cell, a terminal identity, and an existing key;

receiving a second Terminal Identity Token from a UE, the second Terminal Identity Token being generated by the UE based on the physical cell identity of the target cell, the terminal identity, and the existing key; and

identifying the UE in the target radio base station based on the received Terminal Identity Tokens.

10. The method according to claim 9, further comprising:

identifying the UE in the target radio base station by comparing the first and second Terminal Identity Tokens, wherein both the first and second Terminal Identity Tokens are created in response to the terminal identity and the existing key.

11. The method according to claim 10, wherein the second Terminal Identity Token is generated as a Pseudo Random Function using the terminal identity, the existing key, and other parameters as input.

12. The method according to claim 10, wherein the first Terminal Identity Token is generated as a Pseudo Random Function using the second Terminal identity Token and other parameters as input.

13. A User Equipment (UE) adapted to identify itself, the UE being connectable to a first radio base station in a radio system and adapted to communicate with a second radio base station of the radio system via a secure communication associated with a unique existing encryption key, and wherein said UE is configured to:

create the Terminal Identity Token based on a physical cell identity of a target cell known to both the UE and the first radio base station, the terminal identity and the existing key; and

transmit the Terminal Identity Token to one of the first and second radio base stations of the radio system as an identity of the UE.

14. The UE according to claim 13, wherein the UE is configured to use additional input parameters as input data when creating the Terminal Identity Token.

15. The UE according to claim 13, wherein the use is configured to create the Terminal Identity Token using a Pseudo Random Function.