# A Practical Implementation of Post-Quantum Cryptography for Secure Wireless Communication +
## 6 Evaluation
### Results and Discussion
#### 6.2.3 Impact of PQC Algorithms on Performance in the File Transfer Use Case
These results emphasize hybrid protocols'  
Figure 7: Throughputs of the encrypted files: (a) 1 KB file. (b) 10 KB file. (c) 100 KB file. potential to mitigate PQC overheads, particularly for larger data volumes, while reaffirming AES-256's fixed efficiency for mid-sized operations. Throughput  
Furthermore, the server-side throughput results shown in Figure 7, categorized by 1 KB, 10 KB, and 100 KB file sizes, illustrate the interplay between ciphertext dimensions and quantum-resistant algorithm performance relative to AES-256. Figure 7a shows results for the 1 KB data, confirming that AES-256 achieved a throughput of 0.170 Mbps, while the PQC standalone methods with larger ciphertexts, such as HQC-128-F1024, reached 7.841 Mbps, a 46.1-fold increase. This variation arose not from superior efficiency but from expanded ciphertext sizes increasing the throughput metrics. It was observed in the hybrid implementations that the CRYSTALS-Kyber algorithm paired with the FALCON digital signature achieved throughput results comparable to AES-256. The results show total throughput values of K512-F512 (0.476 Mbps), K768-F512 (0.517 Mbps), K512-F1024 (0.554 Mbps), and K768-F1024 (0.647 Mbps). Additionally, Figure 7b shows that at 10 KB, AES-256 throughput dropped to 0.0035 Mbps, whereas PQC standalone total throughput increased. K1024-F512 achieved a total throughput of 19.516 Mbps, reflecting the compounding effect of ciphertext expansion on throughput. BIKE-L1-F512 followed this trend at 10.578 Mbps, although its larger ciphertexts inherently amplified throughput values despite slower absolute processing speeds. For the hybrid modes, HQC-256-F512 showed a total throughput of 2.005 Mbps, 565 times higher than that of AES-256. This confirms the higher computational latency  
Figure 8: Round-trip times of the encrypted files: (**a**) RTT for 1 KB file. (**b**) RTT for 10 KB file. (**c**) RTT for 100 KB file. of the PQC standalone algorithm compared to the conventional cryptographic algorithm, underscoring the metric's limitations in isolation. For 100 KB files, as shown in Figure 7c, the AES-256 total throughput further increased to 9.725 Mbps, while PQC standalone K768-F1024 also increased to 33.320 Mbps, 3.4 times higher than AES-256. This disparity arose from the file size and ciphertext increase, as PQC algorithms produce larger ciphertexts than AES-256. BIKE-L1-F1024 achieved 11.968 Mbps in PQC standalone mode, while its hybrid variant (7.459 Mbps) lagged, emphasizing the trade-offs between post-quantum security and protocol complexity. Notably, BIKE-L5-F512's PQC standalone mode achieved a throughput (4.476 Mbps) lower than AES-256 by a factor of 1.9, despite its larger ciphertexts, highlighting vulnerabilities in the scalability of code-based algorithms. These results underscore that while PQC algorithms may exhibit higher throughput due to ciphertext expansion, this metric alone does not capture their operational efficiency or suitability for latency-sensitive applications. The results demonstrate that although larger ciphertext sizes in PQC algorithms result in higher throughput compared to AES-256, this does not directly imply greater efficiency. Round-Trip Time  
The RTT measurements for 1 KB, 10 KB, and 100 KB file sizes shown in Figure 8 reflect the operational latency introduced by ciphertext expansion and protocol overhead in PQC algorithms, despite their higher throughput metrics. Figure 8a shows the results for 1 KB files. AES-256 recorded an RTT of 0.0115 s, while multiple PQC standalone protocol algorithms achieved slightly lower latencies in comparison. HQC-128-F1024 achieved 0.0022 s, 5.2 times faster than AES-256, and K512-F512 achieved 0.0024 s. In the hybrid implementations, however, the algorithm pairs incurred slightly lower latencies than AES-256, while K1024-F512 (0.0115 s) achieved similar latency, underscoring the handshake overhead inherent to hybrid protocols.