• Farshad Rahimi Ghashghaei
• Yussuf Ahmed
• Nebrase Elmrabit
• Mehdi Yousefi

• Farshad Rahimi Ghashghaei, Yussuf Ahmed, Mehdi Yousefi: School of Computing and Digital Technology, Birmingham City University, Birmingham, United Kingdom
• Nebrase Elmrabit: Department of Cyber Security and Networks, Glasgow Caledonian University, Glasgow, United Kingdom

Within the core main.py file, Three PQC algorithms, Kyber for key encapsulation, Dilithium and Falcon for authentication, have been combined with QKD BB84 quantum simulation. This integration improves code structure and makes it easier to compare these algorithms' assessments across our cryptosystem.

• Kyber.py: Contains the implementation of the Kyber algorithm, offering functionalities for key encapsulation following the CRYSTALS-Kyber scheme.

• Dilithium.py: Hosts the implementation specific to the Dilithium algorithm, managing digital signatures according to the CRYSTALS-Dilithium scheme.

• Falcon.py: Houses the code for the Falcon algorithm, which handles digital signatures in alignment with the Falcon scheme.

To implement PQC algorithms, we rely on external libraries sourced from the following open-source projects:

• GiacomoPope/kyber-py
• GiacomoPope/dilithium-py
• tprest/falcon.py

This table presents the key generation times (in milliseconds) for different security levels of the PQC algorithms.

This table showcases the encapsulation, signing, decapsulation, and verification times (in milliseconds) for various combinations of PQC algorithms.

These tables present the sizes (in bytes) of the ciphertexts and signatures for different PQC algorithms.

• The choice of the best security level for cryptographic algorithms like CRYSTALS-Kyber, CRYSTALS-Dilithium, and Falcon depends on striking a balance between security requirements and resource constraints.
• Higher security levels such as Kyber 1024, Dilithium 5, and Falcon 1024 offer stronger security assurances but come with larger signatures and slower cryptographic procedures.
• For most practical purposes, options like Kyber 768, Dilithium 3, and Falcon 256 provide a well-balanced compromise between security and performance.
• While Falcon excels in signing and verification, its key generation performance may be suboptimal.
• Ultimately, the best security level must be tailored to the specific security needs and performance limitations of the application at hand.