## 4 Results
This increase in time reflects the enhanced security and encryption offered by these algorithms. Achieving the right balance between security and time efficiency is crucial for specific use cases. Figure 5: Signature sizes. Figure 6: Ciphertext sizes. Figure 8: Kyber 768 encapsulation. Figure 9: Kyber 1024 encapsulation. Figures 13 and 14 illustrate the performance of three Kyber post-quantum cryptographic variants (Kyber 512, Kyber 768, and Kyber 1024) in terms of total data size (x-axis in bytes) and processing time (y-axis in milliseconds). Each point on the graph represents a digital signature that is combined with the specified Kyber variant. In Figure 13, starting from Falcon 256, the graph progresses to Falcon 512 and Falcon 1024, demonstrating the variations in processing time concerning different signature sizes. In Figure 14, the focus shifts to Dilithium, with points corresponding to Dilithium 2, Dilithium 3, and finally Dilithium 5. This comprehensive visualization provides insights into the trade-offs between signature size and processing time for each cryptographic scheme. For Kyber 512, processing time increases with data size, and a similar trend is observed for Kyber 768 and Kyber 1024. These figures are valuable documents for selecting the appropriate Kyber variant tailored to specific application needs, allowing for a well-informed decision that balances security and efficiency considerations. Kyber 512 offers quicker processing for smaller data sizes, while Kyber 1024 provides higher security at slightly longer processing times. Figure 11: Kyber 768 decapsulation. Figure 12: Kyber 1024 decapsulation. Figure 10: Kyber 512 decapsulation. Additionally, Tables 8-11 offer an in-depth overview of all cryptographic settings, showing the complex relationships between cipher sizes, signature sizes, and the time needed for key operations. As we peruse the data, we discern intriguing patterns and trade-offs. For instance, increasing the security level of cryptographic algorithms, such as transitioning from Kyber 512 to Kyber 1024, leads to larger cipher and signature sizes. However, this enhancement in security comes at a cost, as both encapsulation and signing times also increase. Notably, the signature size experiences substantial variations as we switch between Dilithium and Falcon, showcasing how different signature algorithms can drastically alter the size of the digital seal appended to messages. In contrast, the cipher size remains fairly stable within each security level of the Kyber algorithm, emphasizing that the core encryption method has a more consistent impact on the size of the encrypted data. This insight into the relationship between signature schemes and signature size versus the influence of encryption algorithms on cipher size provides valuable guidance for tailoring cryptographic solutions to specific security and efficiency requirements. To have a logical comparison between PQC schemes and RSA, we choose to compare the three security levels of PQC algorithms with RSA key sizes of 3072, 7680, and 15,360 bits. In order to achieve the optimal balance between the security and performance of PQC schemes, we used RSA as secure KEM and digital signature to gain similar results to previous ones. Table 12 shows the performance of different key sizes, which also demonstrates the security of RSA. Figure 3:0 Performance comparison of authenticated-encryption schemes (using CRYSTALS-Dilithium). Figure 3:1 Performance comparison of authenticated-encryption schemes (using Falcon). From these results of RSA performance and security levels, we choose Kyber 512 with Dilithium 3 as the optimal combination that has a great balance between security and speed. When comparing the choice of Dilithium 3 with Kyber 512 against RSA and Falcon combinations, several factors influence the decision. RSA offers dual functionality as both a digital signature and a KEM, with established security but increasingly longer key