CPC H04L 9/083 (2013.01) [H04L 9/0816 (2013.01); H04L 9/0869 (2013.01); H04L 63/062 (2013.01); H04W 8/20 (2013.01); H04W 12/041 (2021.01); H04W 12/0471 (2021.01); H04L 2209/24 (2013.01); H04L 2209/80 (2013.01); H04L 2463/061 (2013.01); H04W 92/10 (2013.01)] | 16 Claims |
11. A user equipment (UE), the UE comprising:
processing circuitry;
wherein:
the UE is arranged to establish a security key for protecting Radio Resource Control/User Plane traffic exchanged with a serving radio base station; and
the processing circuitry is configured to:
send a Non access Stratum (NAS) message containing a NAS service request to a mobility management entity (MME), the NAS message indicating a NAS uplink sequence number; and
derive the security key from at least said indicated NAS uplink sequence number and from a stored access security management entity-key shared with said mobility management entity, using a key derivation function taking the NAS uplink sequence number and the stored access security management entity-key as inputs.
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