| CPC H04W 36/362 (2023.05) [H04W 12/041 (2021.01); H04W 88/06 (2013.01)] | 25 Claims |
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1. A user equipment configured to support dual connectivity operation towards a master node and a secondary node of a radio access network, the user equipment comprising at least one processor and at least one memory, the at least one memory storing instructions that, when executed by the at least one processor, cause the user equipment to perform at least the following:
establishing a connection towards the master node;
receiving configuration information from the master node, wherein the configuration information comprises key counter information which defines a sequence of at least two different key counter values to generate at least two different security keys for at least two different target secondary nodes; wherein a first target secondary node is configured for a first conditional PSCell addition or change (CPAC) or a conditional handover (CHO) towards the first target secondary node, and wherein a second target secondary node is configured for a subsequent conditional PSCell addition or change (CPAC) or a conditional handover (CHO) towards the second target secondary node;
generating a first security key using a first key counter value derived from the key counter information;
using the first security key for integrity protection and/or ciphering of data exchanged between the user equipment and the first target secondary node; and
processing the key counter information such that the user equipment is enabled to derive, from the processed key counter information, at least a second key counter value, which is different from the first key counter value,
wherein the generating the first security key comprises using a first list element in a list of key counter values included in the key counter information as the first key counter value, wherein processing the key counter information comprises removing the first list element from the list of key counter values.
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