# HSM4 SSL: Leveraging HSMs for Enhanced Intra-Domain Security +
## 4 HSM4 SSL Performance
### Results and Discussion  
Figure 10 shows that both HSM4 SSL and OpenSSL have a roughly steady and consistent RPS rate as the number of concurrent users increased from 1 to 100, suggesting that both systems demonstrated an ability to handle an increasing workload without a significant drop in RPS, emphasizing their scalability under the test conditions. However, HSM4 SSL consistently exhibits a higher RPS compared to OpenSSL at various user load levels. This indicates the remarkable efficiency and scalability of HSM4 SSL in processing a greater number of requests in parallel. Plus, Figure 11 reveals that, as the number of concurrent users increases in the same range, both HSM4 SSL and OpenSSL exhibit a gradual increase in latency, which is expected as system loads intensify. However, on \begin{table}
\begin{tabular}{l l} \hline \hline
**Specification** & **Details** \\ \hline Operating System & Ubuntu 22.04 \\ \hline Processor & AMD Ryzen 7 \\ \hline Memory & 16 GB \\ \hline Hard Drive & 1 TB SSD \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Hardware specifications. average, the latency for each request served by OpenSSL tends to be 13.08% higher than that of HSM4 SSL. Another evaluation criterion is the evaluation of resource and network utilization, where CPU usage was determined by closely monitoring essential components, namely Python, Google Chrome, and the MySQL database, for the HSM4 SSL architecture. An interesting observation from the results shown in Figure 12 is the clear and consistent logarithmic growth exhibited by HSM4 SSL and OpenSSL. However, HSM4 SSL's growth in CPU usage is more pronounced compared to OpenSSL since HSM4 SSL includes more complex backend processes, such as generating the ADCP message, forwarding the message to multiple managers, generating the policy set, and accessing databases to save or retrieve information. Throughout the tests, HSM4 SSL showcases an ability to efficiently utilize CPU resources, as evidenced by the substantial growth in CPU usage. This growth, although higher, eventually stabilizes at a maximum of 15.6%. This is because the application or  
Figure 11: Latency comparison results. Figure 10: RPS comparison results. processes included in HSM4 SSL may be configured with resource allocation limits that restrict its ability to consume more than a certain percentage of the CPU's total capacity. The network utilization concentrates on understanding the influence of certificate generation on network resources, specifically focusing on HSM4 SSL. Notably, OpenSSL operates and is utilized locally within each server, making the monitoring of network utilization primarily relevant to HSM4 SSL. Figure 13 shows a consistent upward trajectory in network bandwidth consumption by HSM4 SSL. However, it is noteworthy that the network bandwidth utilization eventually stabilizes at approximately 690-700 KB/s. This cap indicates that HSM4 SSL, while efficiently scaling to meet growing demands, has an upper limit in terms of network resource utilization. This stability underscores the architecture's ability to effectively allocate and manage network resources without excessive saturation. Based on the evaluation outlined, multiple methods can be involved to enhance the performance of HSM4 SSL. The evaluation of HSM4 SSL shows a weakness in CPU usage. To reduce CPU utilization caused by MySQL processes, one strategy is to implement database-caching mechanisms. Caching frequently accessed data can reduce the computational load on the CPU by minimizing the need to repeatedly retrieve data from the database. Plus, by utilizing more parallelization techniques, HSM4 SSL can reduce the latency and processing  
Figure 12: CPU usage comparison results. Figure 13: Network bandwidth comparison results. time by enabling the simultaneous execution of multiple certificate generation requests.