Methods, nodes and communication device for establishing a key related to at least two network instances

(canceled)

A network node for establishing a key related to at least two network instances, the network instances used in serving a communication device, the network node being configured to:

• obtain a first key relating to at least a first network instance,
• obtain a second key relating to an additional network instance, and
• determine, based on the first key and the second key, a joint key for use in protecting communication with the communication device on the at least first network instance and on the additional network instance.

A method performed in a communication device of establishing a key related to at least two network instances, the network instances used in serving communication device, the method comprising:

• obtaining a first key relating to at least a first network instance,
• obtaining a second key relating to an additional network instance, and
• determining, based on the first key and the second key, a joint key for use in protecting communication with a network node on the at least first network instance and on the additional network instance.

(canceled)

A communication device for establishing a key related to at least two network instances, the network instances used in serving communication device, the communication device being configured to:

• obtain a first key relating to at least a first network instance,
• obtain a second key relating to an additional network instance, and
• determine, based on the first key and the second key, a joint key for use in protecting communication with a network node on the at least first network instance and on the additional network instance.