###### Abstract  
The service-based architecture of the Fifth Generation(5G) had combined the services and security architectures and enhanced the authentication process of services to expand the coverage of the network, including heterogeneous devices. This architecture uses the secondary authentication for mutual authentication between the User Equipment (UE) and the Data Network (DN) to authenticate devices and services. However, this authentication mechanism can cause a signaling storm in the Non-Access Stratum (NAS) because the end node needs to communicate with the authentication server of the NAS area. This problem could affect the availability of the network when the network is extended. This research proposes a mutual authentication framework that can efficiently perform a mutual authentication process through secondary authentication between UE and DN. The proposed framework uses newly devised network functions: Secondary Authentication Function (SAF) and the Authentication Data Management Function (ADMF). This framework proposes a methodology at the protocol level for efficient mutual authentication using the mobile edge computing architecture. We analyzed the proposed framework in the point of security considerations, and we evaluated the effect of the framework on the traffic of the NAS layer and user experience. Our simulation results show that the proposed framework can reduce the NAS traffic by 39% and total traffic of the overall network by 10%. 5G network; secondary authentication; mutual authentication; edge computing 2020  
However, this expansion of connectivity can cause problems in two perspectives. The first problem is that network traffic can explode as the number of devices connected to the network increase, and many services move to cloud platforms [4]. As data collected from a large number of nodes is transmitted to the cloud server, a vast amount of traffic is generated, and the amount of unnecessary traffic on the cloud server increases. The second is the security issue. As different heterogeneous devices are connected, they can cause security problems of communication and protocol to integrate and operate with each other. Functions such as mutual authentication and cryptographic communication are required for data communication between devices [5]. However, there is a limitation that all devices cannot communicate with the same protocol because the performance and operation environment of the devices are different. For compatibility of each device, there may be a point where sufficient security requirements are not satisfied in the operation of proper authentication and communication protocols. The more devices connected and the more diverse the network, the higher the number of these points, and the more difficult it becomes to prevent attackers from spreading malicious devices or data breaches through these points [6]. The 5G network architecture aims to improve the efficiency of communication and to solve security problems by including service areas in the network security architecture. To expand the area of network and to support various types of services and devices, the 5G architecture provides primary and secondary authentication for users and services [7]. When a user accesses a service network, the user can be authenticated not only on the network but also on the service network. This secondary authentication increases the compatibility between the device and the service area, solving the security vulnerabilities that may exist in the communication process [8]. However, this mutual authentication process can exacerbate the traffic problem of the network. The traffic generated by secondary authentication is transferred to the 5G home network area. When authentication for the terminal devices is frequently requested, this may put a load on the central home network [9]. Also, the fact that the authentication traffic is transmitted to the home network can cause a vulnerability that allows an attacker to intentionally generate traffic and perform a DoS attack on the entire network.