Updating Encryption Keys in a Radio Communication System

• US 20110135097A1
• Filed: 10/14/2010
• Published: 06/09/2011
• Est. Priority Date: 10/14/2009
• Status: Abandoned Application

• Current Assignee: Tait Limited
• Original Assignee: TAIT Electronics Limited (TAIT Foundation)
• Inventors: Hopgood, Lionel James, Redfern, Andrew David, Smith, Hamish Andrew, Hooker, Guy Alexander
• Application Number:
  US12/904,268
• Publication Number:
  US 20110135097A1
• Time in Patent Office: Days
• US Class Current: 380/279
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 9/0833 involving conference or group key network architectures or network communication protocols for key management in group communication in a packet data network H04L63/065
• 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
• CPC Class Codes: H04W 12/0433 Key management protocols
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

Encryption keys in a communication system are updated according to rekey groups having a common set of encryption keys or CKRs. Each group includes a number of radios with active and inactive keysets. A database records the relationships between rekey groups and keys, and the status of their keysets. An operator first determines one or more keys to be updated. New keys are then transmitted to each radio in one or more rekey groups using respective rekey messages. The new keys are stored in the inactive keysets of the radios. The inactive keysets are then activated using respective changeover messages. Deployment of new keys is carried out by software in the form of automated update tasks.

Claims

1. A method for updating encryption keys in a radio communication system, including:

defining one or more rekey groups containing radios having one or more shared encryption keys,

determining one or more existing keys to be updated with new keys,

transmitting the new keys to each radio in one or more rekey groups, using respective rekey messages,

storing the new keys in inactive keysets of respective radios, and

activating the inactive keysets in the rekey groups to become active keysets, using respective changeover messages.

2. The method of claim 1 wherein the steps of sending rekey messages and changeover messages are carried out automatically for each group once initiated by an operator.

3. A key management facility for a radio communication system having terminals arranged in groups with active and inactive keysets for encrypted communications within the groups, including:

an operator interface,

a communication unit which sends and receives messages to and from the communication system,

a database which stores encryption data relating to the groups,

a cryptographic module which calculates new encryption keys for the groups when required by the operator, and

a scheduling subsystem which transmits rekey messages containing new keys to the groups for respective inactive keysets, and transmits changeover messages which cause the terminals to switch between active and inactive keys.

4. The method of claim 3 wherein the scheduling subsystem sends the rekey messages and changeover messages to the respective groups automatically once initiated by an operator.

5. A method of updating encryption keys in a radio communication system having a plurality of radios assigned to rekey groups, including:

creating a first update task relating to one or more of the rekey groups,

creating a second update task relating to the same or a different rekey group, each task involving deployment of one or more new keys to the respective groups,

initiating the first and second update tasks, and

executing the update tasks subject to conditions determined by any conflict between the two tasks.

6. The method of claim 5 wherein the conditions include a delay of one task while awaiting progress of the other task.