## 5 Conclusions  
MANET are frameworks designed for temporary use in various situations. Depending on the application, they can easily scale their structure and flexibly accommodate participating nodes. In such environments, establishing efficient routes between the source and target groups is a critical issue in MANET. However, MANET operate as multi-hop networks where data are relayed by nodes with limited capabilities. Due to these characteristics, route establishment becomes challenging, and the involvement of multiple nodes in route setup and data transmission makes the network highly susceptible to security threats. In particular, data forgery and tampering attacks by malicious nodes can severely degrade network performance, and such threats are amplified in group communication scenarios like multicast.  
This paper proposes a zone-based structure to reduce control overhead and optimize route establishment in MANET multicast environments. To enhance resilience against malicious attacks and improve the reliability of transmitted data, a two-step authentication key and group key mechanism are applied. The contributions of the proposed method are as follows:  
Reduction in Control Overhead and Optimized Routing: By dividing the network into zones, the proposed method minimizes control overhead and optimizes data trans  
Figure 10: Experimental results for 30 multicast group sizes. (**a**) Packet delivery rate; (**b**) number of control packets; (**c**) average path length; (**d**) average path delay.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Proposed Method** & **PAST-DM** & **MSZRP** \\ \hline Packet transmission rate (\%) & 91 & 87.6 & 89.3 \\ Number of control packet & 5147 & 5802 & 5746 \\ Average path length (hop) & 4.3 & 4.6 & 4.4 \\ Average path delay (sec) & 0.57 & 0.75 & 0.73 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Average results by performance metrics.  
mission paths, ensuring stable and reliable multicast performance even in the presence of node mobility.  
Dynamic Multicast Group Membership Management: The proposed method enables efficient adaptation to dynamic multicast group membership changes through an effective group management mechanism.  
Enhanced Security via Hierarchical Key Management: By employing hierarchical key management, the method ensures secure data transmission and prevents malicious nodes from joining the multicast group.  
Consistent and Secure Membership Management: Node authentication and inter-zone group node table updates support dynamic membership management, ensuring consistent and secure handling of node mobility.  
The performance of the proposed method was evaluated in detail. Simulation results demonstrate the efficiency of the proposed protocol in discovering and maintaining routes compared to three benchmark protocols. The proposed method exhibited superior scalability, maintaining consistent performance under varying mobility speeds, numbers of sources, and multicast group sizes. However, future research will focus on optimizing node authentication and table management to address energy consumption concerns for nodes participating in the network.  
This paper was supported by Joongbu University Research & Development Fund, in 2023.  
**Institutional Review Board Statement**: Not applicable.  
**Informed Consent Statement**: Not applicable.  
**Data Availability Statement**: The [simulated evaluation] data used to support the findings of this study are included within the article.  
**Conflicts of Interest**: The authors declare no conflicts of interest.