The evolution of every communication standard provides high connectivity among the communication devices.5G and other beyond technologies are being designed to catering diverse requirements of use cases. To realize such features of 5G and beyond technologies, we need to rethink how the current cellular networks are designed and established. Because, the radio communications and spectrum utilizations are not enough. Several technologies such as Software Defined Networking (SDN), Network Function Virtualization (NFV), Machine Learning, and Cloud Computing are currently used to establish the 5G communication technology. Also, it creates some challenges such as decentralization, transparency, interoperability, privacy, and security. To address these issues, we can integrate Blockchain into 5G. Because Blockchain has the features such as transparency, immutability, encryption and distributed environment. Even though blockchain provides a secure and reliable communication, there are some possible attacks such as Denial of Service (DoS), Eavesdropping, Man in the Middle (MitM) and jamming. We designed a secure authentication protocol which eradicates the above-mentioned attacks. It performs mining process, verify the timestamp and aggregate the transaction. It reduces the communication overhead and computation time. Our security analysis illustrates that the proposed scheme is secure and resists the known attacks such as DoS, DDoS, MitM, hijacking and compromising attacks.

Blockchain,5G, SDN, Cloud RAN,5G, DoS, DDoS, Hijacking, Jamming, AKA, Authentication