## 5 Evaluation of the Security Aspects of the Designed Protocol
### Informal Security Evaluation of the Suggested Protocol
#### 5.1.2 Impersonation Attack  
Whenever the adversaries within the network desire to establish themselves as an authenticated node capable of utilizing network resources and interacting with other nodes, they deploy this attack to realize their objectives. To thwart this attack, we have utilized the authentication mechanism at various stages and incorporated the private parameters of communication entities to augment both security and the distinctiveness of the calculated values. As mentioned in the protocol description, Ni is the initial parameter employed by both the node and the server in performing the authentication process. The security of this parameter is guaranteed by its transmission via a secure channel and its computation using the private keys of both the node and the server, as per the Elliptic Curve Diffie-Hellman(ECDH) protocol. To enhance the security robustness of the protocol, we avoid dependency on the authentication of the node and server to a single parameter, instead incorporating parameters A, S2, S3, and S4 into the authentication process. Considering the principle of confidentiality of these parameters and utilization of them in the protocol process for the authentication mechanism and session-key generation, in order to maintain their security and also to meet security features such as non-dependence, ensuring unpredictability, random numbers are utilized to generate parameters A, S2, S3, and S4. This combination guarantees that the parameters generated by the node and the server in the process of authentication and session-key generation are completely unique for each communication session. For enhanced security of the generated parameters, alongside utilizing the features of random numbers, we have incorporated the private parameters of both the node and the server, which are exchanged through a secure channel. As outlined in the conditions, the security mechanism utilized for the parameters generated within the protocol process guarantees the security of both communication entities during the protocol execution and prevents the occurrence of an impersonation attack. For a better understanding, we will continue to evaluate the S3 parameter calculation. To produce this parameter, it is necessary to calculate and access the following parameters.  
1. **Calculation of S1:** To compute this parameter, the node employs a technique where its private key is combined with random elements. This strategy mitigates the risk associated with exposing the private key directly and ensures that the resultant value is unique for every session.
2. **The Ni parameter:** This parameter is also generated using random numbers in order for it to be unique in each communication session.
3. **The AC\({}_{\text{i}}\) parameter:** Created during the registration of the node, this parameter is maintained as private by both the node and the server.
4. **Parameter A:** This parameter is calculated using confidential values of S1, Ni, and AC\({}_{\text{i}}\).
5. **S\({}_{2}\)**: This is the combination of S\({}_{1}\), the X dimension of N\({}_{\text{i}}\), K, and A parameters.  
Also, in order to obtain the encryption key, it needs the server's private key or the disclosure of private numbers. Given that a multitude of necessary private parameters are required and the protection of these parameters is maintained in the protocol process, it is impossible for a hostile person to access S\({}_{3}\).