Method and apparatus to implement security in a long term evolution wireless device

1. A wireless transmit/receive unit (WTRU) comprising a processor configured, at least in part, to:

receive a non-access stratum (NAS) message comprising a NAS sequence number (NAS SN);

construct a count value based on the NAS SN and a NAS counter that increments based on the value of the NAS SN; and

perform an integrity check on the NAS message by using the count value as an input to an integrity algorithm.

2. The WTRU of claim 1 , wherein the processor is configured to:

handle the received NAS message based on the integrity check, wherein on a condition that the received NAS message fails the integrity check, the NAS message is discarded, and on a condition that the received NAS message passes the integrity check, the NAS message is processed.

3. The WTRU of claim 1 , wherein the processor is configured to:

perform at least one of the following on a condition that the received NAS message fails the integrity check:

report a failure to another protocol layer;

initiate a re-authentication, moving to Evolved Packet System (EPS) Mobility Management (EMM_Idle) mode;

move to EMM_Deregistered state;

maintain a count of a number of failures;

proceed to re-attach to a network; or

delete security parameters.

4. The WTRU of claim 1 , wherein the processor is configured to:

perform duplicate detection based on at least one of the NAS sequence number or the count value.

5. The WTRU of claim 1 , wherein the NAS sequence number functions as a transaction identifier.

6. The WTRU of claim 1 , wherein the NAS sequence number is associated with a pre-defined incrementing period.

7. The WTRU of claim 1 , wherein the NAS sequence number is associated with a negotiated incrementing period.

8. The WTRU of claim 1 , wherein the count value is configured before NAS security activation.

9. The WTRU of claim 1 , wherein the count value is 32 bits in length.

10. The WTRU of claim 1 , wherein each of the NAS SN and the NAS counter are configurable.

11. A method comprising:

receiving a non-access stratum (NAS) message comprising a NAS sequence number (NAS SN);

constructing a count value based on the NAS SN and a NAS counter that increments based on the value of the NAS SN; and

performing an integrity check on the NAS message by using the count value as an input to an integrity algorithm.

12. The method of claim 11 , further comprising:

handling the received NAS message based on the integrity check, wherein handling the received NAS message based on the integrity check comprises:

discarding the NAS message on a condition that the received NAS message fails the integrity check, and

processing the NAS message on a condition that the received NAS message passes the integrity check.

13. The method of claim 11 , further comprising:

performing at least one of the following on a condition that the received NAS message fails the integrity check:

reporting a failure to another protocol layer;

initiating a re-authentication, moving to Evolved Packet System (EPS) Mobility Management (EMM_Idle) mode;

moving to EMM_Deregistered state;

maintaining count of number of failures;

proceeding to re-attach to a network; or

deleting security parameters.

14. The method of claim 11 , further comprising:

performing duplicate detection based on at least one of the NAS sequence number or the count value.

15. The method of claim 11 , wherein the NAS sequence number functions as a transaction identifier.

16. The method of claim 11 , wherein the NAS sequence number is associated with a pre-defined incrementing period.

17. The method of claim 11 , wherein the NAS sequence number is associated with a negotiated incrementing period.

18. The method of claim 11 , wherein the count value is configured before NAS security activation.

19. The method of claim 11 , wherein the count value has a length of 32 bits.

20. The method of claim 11 , wherein the NAS SN and the NAS counter are configurable.