# Post-Quantum Key Exchange and Subscriber Identity Encryption in 5G Using ML-KEM (Kyber) 1
## 6 Experimentation and Performance Analysis
### Computational Time Performance Analysis  
As described in Section 5 the UE performs public- and shared-key generation, encapsulation, and encryption processes before transmitting the data to the CN side for decapsulation and decryption. We evaluate and compare the computation times required for generating public keys and shared keys using pre-quantum ciphers (X25519 and secp256r1) and a post-quantum cipher (Kyber-512) on two resource-constrained devices \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Device** & **Entity** & **CPU Specs** & **RAM (GB)** & **OS** \\ \hline Computer & CN \& UE & AMD Ryzen 7 5700U 1.8 GHz & 16 & Ubuntu 16.04 LTS \\ \hline MiniPC & UE & Intel 12 th N95 3.4 GHz & 8 & Ubuntu 16.04 LTS \\ \hline Raspberry Pi B+ & UE &
\begin{tabular}{c} BCM2711, Quad-core \\ Cortex-A72 1.8 GHz \\ \end{tabular} & 4 & Ubuntu 16.04 LTS \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Hardware specification of our experimental setup. (Raspberry Pi and Mini-PC) at the UE side, as shown in Figure 3a and Figure 3c, respectively. We also compare the computational time duration for public-key generation among three ciphers at the CN side. This is essential because the CN requires a more robust device, and the Mini-PC and Raspberry Pi are not suitable for serving as the primary CN device due to limited computing resources, such as processing power, memory, storage, and energy, but the UE can be resource-constrained devices. The CN uses a computer to generate its public key, which the UE then uses to conceal the SUPI during the SUCI generation process. The speed at which the CN can generate this public key directly impacts the overall authentication latency. As shown in Figure 3b, Kyber-512 completes public-key generation in just 3.95 us, while X25519 and secp256r1 take 27.3 us and 22.5 us, respectively. This means that Kyber-512 is approximately 85.5% faster than X25519 and 82.4% faster than secp256r1. The substantial reduction in computation time makes Kyber-512 a highly efficient choice for the CN, enabling faster response times and better scalability in post-quantum secure 5G authentication. Figure 3a shows the computation time for public key generation on the Raspberry Pi and Mini-PC because the UE's public key is used by the CN to de-conceal the SUPI from the received SUCI. By using the Raspberry Pi as a UE, the computational time comparison shows that, for Kyber-512, the public-key generation requires 20.48 us, which is 82.88% and 82.67% less time consumption than X25519 and secp256r1 have, with 120.7 us and 118.7 us,  
Figure 3: Computational time performances on computer, Mini-PC, and Raspberry Pi. The average values and the 95% confidence intervals are shown, although they may not be too visible. (**a**) Public key generation time (UE); (**b**) public key generation time at CN (computer); (**c**) shared key generation time (UE); (**d**) shared key generation time (computer). respectively. For the Mini-PC, Kyber-512 consumes 6.038 us, X25519 takes 42.66 us, and secp256r1 requires 35.8 us. Kyber-512 exhibits a significant advantage, taking 85.76% and 82.95% less time than X25519 and secp256r1, respectively. Figure 3a also shows that the Raspberry Pi requires more time compared to the Mini-PC for all three ciphers. This is because the computing resources of Raspberry Pi are fewer than the Mini-PC. Similarly, we also measure the computational time for shared-key generation on the Raspberry Pi and Mini-PC as shown in Figure 3c because the shared key is used for encapsulation at the UE side and decapsulation at the CN side. The shared-key generation time on the Raspberry Pi is reduced significantly, standing at 68.57% and 74.69% less than X25519 and secp256r1, respectively, while the results of the time required to generate a shared key on the Mini-PC show that the post-quantum cipher Kyber-512 takes 28 us, demonstrating efficiency, utilizing 57.90% and 74.66% less time than X25519 and secp256r1, with 66.51 us and 110.3 us, respectively.