1. A method of generating a cryptographic key for protecting communication between a user equipment and a network entity comprising a mobility management entity, the method carried out by a cryptographic key generation device comprised in the user equipment as part of an Authentication and Key Agreement (AKA) procedure initiated by the network entity, the method comprising: providing at least two parameters, wherein a first parameter comprises or is derived from a Cipher Key (CK) and an Integrity Key (IK) computed by the user equipment by running the AKA procedure, and wherein a second parameter comprises or is derived from an authentication token (AUTN), the authentication token comprising an exclusive OR of a sequence number (SQN) and an Anonymity Key (AK); and applying a key derivation function to generate a cryptographic key based on the provided parameters.