# Quantum Key Distribution for 5G Networks: A Review, State of Art and Future Directions
## 2 Security Challenges in 5G Network
### Access Control  
Performing selective limitation of the access for the network is the main purpose of access control. Since access control is the main component for any network security system,securing and providing a safe network to end-users is crucial for network providers. The authentication of user access is confirmed in the access control environment. The concept of access control strategies shows at the implementation-independent level before applying to real-time systems using accessibility policies systems. Several current access control systems show that network decentralization can upgrade the security of the network system environment. Research in [32] investigates access selection schemes for device-to-device physical layer security with different eavesdroppers. Taking distance threshold into consideration, the authors proposed sharing the spectrum between D2D devices and cellular users. The interference generated is used to confuse the eavesdroppers using jamming. The authors use the D2D protection pair to secure a single user and optimal throughput access selection scheme to increase securities. Furthermore, in [33], the authors introduced an automated framework called ConfigSynth to synthesize network security configurations and provide affordable network configuration. The author improved the security framework by designing a refinement mechanism. The algorithm is used to offer better security device distribution, isolation, and improved traffic flow. In [34], the authors update LTE pseudonyms by utilizing the current pseudonym-based solutions to prevent International Mobile Subscriber Identity (IMSI) downgrade attacks using fake base stations. Various access control solutions have been proposed based on authentication, encryption, authorization, and secret sharing. The authors in [35] proposed a privacy-preserving and accountable access control to guarantee user privacy. The validity of the protocol is authenticate using restricted experimental resources. Meanwhile, the authors in [36] introduced a biometric and password-based authentication scheme for Telecare Medicine Information System (TMIS). The proposed solution works by offering anonymity, authentication, forward secrecy, and lower computational cost without the involvement of a remote server. Moreover, a general verification scheme for access control policies is proposed to expand the current management and policy specification [37]. An access control scheme for IoT based on the computer outsourcing and ciphertext update is presented by authors in [38]. The proposed method uses attribute-based encryption (ABE) to encrypt the user's data before storing the data into cloud storage. [PERSON] et al. offered an efficient and secure data sharing scheme for Online Social Networks (OSNs) that are developed using secret sharing and Ciphertext-Policy Attribute-Based Proxy Re-Encryption (CPABPRE) [39]. The authors also reduced the computational overhead by introducing partial decryption construction. The construction distributes the decryption process to OSNs, examine the ability mechanism to ensure decrypted data by OSNs, attribute revocation technique to attain forward and backward secrecy. Moreover, authors in [40] proposed a node admission protocol using secured ephemeral mobile ad-hoc network (MANET) using bi-variate polynomial secret sharing. The proposed scheme is a secure admission method to ensure sharing, efficiency, and non-interactive. MANETs are permitted to distribute efficiently and secretly pairwise secret keys without any assistance from a centralized system. The authors also develop a method for creating fast and spontaneous secure communication links from the pair of nodes. [PERSON] et al. introduced shared encryption-based construction (SEBC) access control schemes based on general hierarchical access control [41]. The proposed scheme used symmetric encryption and secret sharing to add authorized users to the system. The scheme allows the management of access to different users and details other methods of accessing the system.