A Comprehensive Experimental Study: Enhancing the Security of Classical Communication with Post-Quantum Authenticated-Encryption Schemes for the Quantum Key Distribution

Authors

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

Affiliations

• 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

Overview

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.

Components:

• 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

Results

Key Generation Times (ms)

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

Security Level	Key Generation (ms)
Kyber512	31.2
Kyber768	78.1
Kyber1024	93.72
Dilithium2	62.42
Dilithium3	93.73
Dilithium5	171.87
Falcon256	6606.39
Falcon512	10016.76
Falcon1024	53601.41

Encapsulation and Signing, Decapsulation and Verification Times

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

Cipher Combination	Encapsulation and Signing (ms)	Decapsulation and Verification (ms)
Kyber 512 and Falcon 256	78.13	78.44
Kyber 768 and Falcon 256	93.72	124.97
Kyber 1024 and Falcon 256	124.97	140.92
Kyber 512 and Falcon 512	124.97	78.07
Kyber 768 and Falcon 512	124.94	140.52
Kyber 1024 and Falcon 512	156.21	156.21
Kyber 512 and Falcon 1024	187.45	109.68
Kyber 768 and Falcon 1024	203.11	156.23
Kyber 1024 and Falcon 1024	250.19	171.86
Kyber 512 and Dilithium 2	187.45	140.52
Kyber 768 and Dilithium 2	422.1	171.84
Kyber 1024 and Dilithium 2	437.77	203.48
Kyber 512 and Dilithium 3	359.29	171.83
Kyber 768 and Dilithium 3	593.94	203.07
Kyber 1024 and Dilithium 3	453.01	234.37
Kyber 512 and Dilithium 5	656.02	249.94
Kyber 768 and Dilithium 5	718.61	296.77
Kyber 1024 and Dilithium 5	1000.07	312.75

Cipher and Signature Sizes

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

Cipher Sizes

Cipher	Cipher Size (bytes)
Kyber 512	768
Kyber 768	1088
Kyber 1024	1568

Signature Sizes for Falcon Algorithm

Falcon	Signature Size (bytes)
Falcon 256	356
Falcon 512	666
Falcon 1024	1280

Signature Sizes for Dilithium Algorithm

Dilithium	Signature Size (bytes)
Dilithium 2	2420
Dilithium 3	3293
Dilithium 5	4595

Notes

• 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 512, 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.