Providing security is one of the key aspects of mobile networks. One of the more obvious reasons is that the wireless communication can be intercepted by anyone within a certain range of the transmitter and with the technical skills and equipment to decode the signaling. There is thus a risk that the data that is transferred can be eavesdropped, or even manipulated, by third parties. There are also other threats; for example, an attacker may trace a user’s movement between radio cells in the network or discover the whereabouts of a specific user. This may constitute a significant threat to users’ privacy. Apart from security aspects directly related to end-users, there are also security aspects related to the ...