Method and system for security enhancement for mobile communications

• US 9,356,785 B2
• Filed: 08/15/2013
• Issued: 05/31/2016
• Est. Priority Date: 02/15/2011
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Buckley, Michael Eoin, Vutukuri, Eswar Kalyan
• Primary Examiner(s): Jhaveri, Jayesh
• Application Number:
  US13/968,059
• Publication Number:
  US 20130336483A1
• Time in Patent Office: 1,020 Days
• Field of Search: 380/255, 370/340, 370/341
• US Class Current: 1/1
• CPC Class Codes: H04L 1/0056 Systems characterized by the type of code used H04L1/08 takes precedence
• CPC Class Codes: H04L 1/0059 Convolutional codes
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 63/0457 wherein the sending and receiving network entities apply dynamic encryption, e.g. stream encryption cryptographic mechanisms or cryptographic arrangements for stream encryption H04L9/065
• CPC Class Codes: H04W 12/03 Protecting confidentiality, e.g. by encryption
• CPC Class Codes: H04W 12/041 Key generation or derivation
• CPC Class Codes: H04W 12/043 using a trusted network node as an anchor
• CPC Class Codes: H04W 12/102 Route integrity, e.g. using trusted paths
• CPC Class Codes: H04W 12/122 Counter-measures against attacks; Protection against rogue devices
• CPC Class Codes: H04W 12/43 using shared identity modules, e.g. SIM sharing
• CPC Class Codes: H04W 12/45 using multiple identity modules
• CPC Class Codes: H04W 12/48 using secure binding, e.g. securely binding identity modules to devices, services or applications
• CPC Class Codes: H04W 12/66 Trust-dependent, e.g. using trust scores or trust relationships
• CPC Class Codes: H04W 12/67 Risk-dependent, e.g. selecting a security level depending on risk profiles
• CPC Class Codes: H04W 12/68 Gesture-dependent or behaviour-dependent
• CPC Class Codes: H04W 12/72 Subscriber identity
• CPC Class Codes: H04W 4/00 Services specially adapted for wireless communication networks; Facilities therefor
• CPC Class Codes: H04W 52/00 Power management, e.g. TPC [Transmission Power Control], power saving or power classes gain control in transmitters or power amplifiers H03G3/3042
• CPC Class Codes: H04W 52/32 TPC of broadcast or control channels
• CPC Class Codes: H04W 80/02 Data link layer protocols

Abstract

A method and system for enhanced security for A5/1 encoding, the method including choosing, at a transmitter, bits within a layer 1 header of a slow associated control channel (‘SACCH’) message for randomization; and setting, at the transmitter, the chosen bits randomly prior to channel coding and encryption of the slow associated control channel message. Further the method may include choosing, at a transmitter, a number of bits to toggle after convolution coding of a message containing a slow associated control channel message, the number of toggled bits being sufficiently low to allow correction at a receiver; and toggling, at the transmitter, said bits based on the channel conditions of the message.

Claims

1. A method comprising:

selecting, by a hardware processor of a wireless transmission device, a field in a layer 1 header of a slow associated control channel (‘

SACCH’

) message associated with a channel, for randomization, wherein the selecting is performed based on a channel condition of the channel or capabilities of a receiver;

setting, by the hardware processor of the wireless transmission device, one or more bits in the selected field in the SACCH message to a random value, wherein the one or more bits in the selected field are at least one of a spare bit, a SACCH repeat order (‘

SRO’

) bit, a fast power control (‘

FPC’

) or enhanced power control (‘

EPC’

) mechanism signaling bit, one or more bits from an order mobile station power level field, or one or more bits from an ordered timing advance field;

performing, by the hardware processor of the wireless transmission device, channel coding and encryption of said SACCH message, wherein said SACCH message includes the one or more bits in the selected field set to the random value; and

transmitting the SACCH message from the wireless transmission device to the receiver.

2. The method of claim 1, wherein the one or more bits from the ordered mobile station power level field are selected to vary a transmit power.

3. The method of claim 1, wherein the one or more bits from the ordered timing advance field are selected to vary timing.

4. The method of claim 1, wherein any of the one or more bits from the ordered mobile station power level field are used if enhanced power control is enabled.

5. The method of claim 1, wherein the field is selected pseudorandomly for each message.

6. The method of claim 1, wherein the field is selected to avoid a predetermined consecutive number of bits of the encrypted slow associated control channel message being the same.

7. The method of claim 6, wherein the predetermined consecutive number of bits are greater than or equal to a length of a key used in a encryption algorithm for generation of a cipher text.

8. The method of claim 1, wherein said encryption is A5/1 encryption in a Global System for Mobile Communications system.

9. The method of claim 1, wherein the channel coding comprises a fire code, convolution code algorithm, interleaving algorithm and a burst mapping after said setting but before said encryption.

10. The method of claim 1, wherein the wireless transmission device is at least one of a mobile device or a Global System for Mobile Communications network node.

11. A wireless transmission device, comprising:

a memory; and

at least one hardware processor communicatively coupled with the memory and configured to;

select, by the at least one hardware processor, a field in a layer 1 header of a slow associated control channel (‘

SACCH’

) message associated with a channel, for randomization, wherein the selection of the field is based on a channel condition of the channel or capabilities of a receiver;

set, by the at least one hardware processor, one or more bits in the selected field in the SACCH message to a random value, wherein the one or more bits in the selected field are at least one of a spare bit, a SACCH repeat order (‘

SRO’

) bit, a fast power control (‘

FPC’

) or enhanced power control (‘

EPC’

) mechanism signaling bit, one or more bits from an order mobile station power level field, or one or more bits from an ordered timing advance field;

perform, by the at least one hardware processor, channel coding and encryption of said SACCH message, wherein said SACCH message includes the one or more bits in the selected field set to the random value; and

transmit the SACCH message from the wireless transmission device to the receiver.

13. The wireless transmission device of claim 11, wherein the one or more bits from the ordered mobile station power level field are selected to vary a transmit power.

14. The wireless transmission device of claim 11, wherein the one or more bits from the ordered timing advance field are selected to vary timing.

15. The wireless transmission device of claim 11, wherein the wireless transmission device is at least one of a mobile device or a Global System for Mobile Communications network node.

16. The wireless transmission device of claim 11, wherein the field is selected to avoid a predetermined consecutive number of bits of the encrypted slow associated control channel message being the same.

12. The wireless transmission device of 11, wherein the wireless transmission device is at least one of a mobile device or a Global System for Mobile Communication network node.