Key Management for Beyond 5G Mobile Small Cells: A Survey

The highly anticipated 5G network is projected to be introduced in 2020. 5G stakeholders are unanimous that densification of mobile networks is the way forward. Densification will be realized by means of small cell technology and it is capable of providing coverage with a high data capacity. The EU funded H2020-MSCA project “SECRET” introduced covering the urban landscape with mobile small cells since these take advantage of the dynamic network topology and optimizes network services in a cost-effective fashion. By taking advantage of device-to-device communications technology, large amounts of data can be transmitted over multiple hops and therefore offload the general network. However, this introduction of mobile small cells presents various security and privacy challenges. Cryptographic security solutions are capable of solving these as long as they are supported by a key management scheme. It is assumed that networkinfrastructureandmobiledevicesfromnetworkusersareunabletoactasacentralizedtrustanchor since these are vulnerable targets to malicious attacks. Security must therefore be guaranteed by means of a key management scheme which decentralizes trust. Therefore, this article surveys the state-of-the-art key management schemes proposed for similar network architectures (e.g., mobile ad hoc networks and ad hoc device-to-device networks)which decentralizes trust.Furthermore,thesekeymanagementschemesare evaluated for adoptability in a network of mobile small cells