Composing Quantum Key Distribution with Superposition-Based Quantum Image Transmission: Confidentiality Without an Additional Reconstruction-Fidelity Penalty
Thisarani Atulugama, Udara Jayasinghe, Anil Fernando
This paper presents a secure image transmission framework for superposition-based quantum communication systems that integrates quantum key distribution (QKD) with one-time-pad encryption. Existing superposition-based image transmission systems achieve reliable image reconstruction over noisy channels but do not provide confidentiality: an eavesdropper intercepting the transmission can recover the image. To address this limitation, we introduce a key-based security layer and analyse its interaction with the quantum modulation and channel coding components. In the proposed approach, a secret key is generated using the BB84 quantum key distribution protocol and then used to encrypt the image data before Hadamard modulation. The system is evaluated both with and without polar channel coding. Simulation results show that encryption does not degrade image quality at the legitimate receiver: its reconstruction performance is indistinguishable from that of the corresponding unsecured baseline under the evaluated conditions. In contrast, the eavesdropper obtains only noise-like plaintext reconstructions, with an empirical PSNR floor of approximately 8.1 dB, even under more favourable channel conditions. Attempts to intercept the BB84 key-generation process remain detectable through the quantum bit error rate. Polar coding provides approximately 8 dB of performance gain for the legitimate receiver; although it can improve ciphertext recovery, it does not improve the eavesdropper’s plaintext reconstruction under the evaluated conditions. These results demonstrate confidentiality without an additional reconstruction-fidelity penalty, while leaving key-rate and protocol costs as separate practical considerations.
This paper presents a secure image transmission framework for superposition-based quantum communication systems that integrates quantum key distribution (QKD) with one-time-pad encryption. Existing superposition-based image transmission systems achieve reliable image reconstruction over noisy channels but do not provide confidentiality: an eavesdropper intercepting the transmission can recover the image. To address this limitation, we introduce a key-based security layer and analyse its interaction with the quantum modulation and channel coding components. In the proposed approach, a secret key is generated using the BB84 quantum key distribution protocol and then used to encrypt the image data before Hadamard modulation. The system is evaluated both with and without polar channel coding. Simulation results show that encryption does not degrade image quality at the legitimate receiver: its reconstruction performance is indistinguishable from that of the corresponding unsecured baseline under the evaluated conditions. In contrast, the eavesdropper obtains only noise-like plaintext reconstructions, with an empirical PSNR floor of approximately 8.1 dB, even under more favourable channel conditions. Attempts to intercept the BB84 key-generation process remain detectable through the quantum bit error rate. Polar coding provides approximately 8 dB of performance gain for the legitimate receiver; although it can improve ciphertext recovery, it does not improve the eavesdropper’s plaintext reconstruction under the evaluated conditions. These results demonstrate confidentiality without an additional reconstruction-fidelity penalty, while leaving key-rate and protocol costs as separate practical considerations.
Quantum image transmission is a critical enabler for next-generation communication systems, allowing for the reliable exchange of high-quality visual data over error-prone quantum channels. Existing quantum-encoding schemes, however, often suffer from limited efficiency and reduced robustness under noisy conditions. This work introduces a novel multi-qubit phase-shift keying (PSK) encoding framework to enhance both fidelity and reliability in quantum image transmission. In the proposed system, source-encoded images (JPEG/HEIF) are converted into bitstreams, segmented into varying qubit sizes from 1 to 8, and mapped onto multi-qubit states using quantum PSK modulation. By exploiting multi-qubit superposition and phase modulation, the scheme improves spectral efficiency while maintaining resilience to channel noise. The encoded quantum states are transmitted through noisy channels and reconstructed via inverse quantum operations combined with classical post-processing to recover the original images. Experimental results demonstrate substantial performance improvements, evaluated using peak signal-to-noise ratio (PSNR), structural similarity index (SSIM), and universal quality index (UQI). Compared to superposition-only approaches, the proposed method achieves up to 3 dB SNR gain for higher qubit sizes, while single-qubit encoding remains limited due to reduced phase utilization. Moreover, relative to classical communication systems, the proposed multi-qubit PSK scheme consistently outperforms across all tested qubit sizes, highlighting its effectiveness for reliable, efficient, and high-fidelity quantum image transmission.
Quantum communication systems have the potential to revolutionize media transmission technologies with unparalleled efficiency and reliability. However, practical and scalable implementations are challenged by issues such as channel fading and interference. To address these, we propose a novel approach combining quantum superposition with transmit and receive diversity schemes in Multiple-Input Multiple-Output (MIMO) systems, designed to mitigate the effects of fading for enhanced image transmission. In our simulations, images in JPEG and HEIF formats are channel encoded with rate 1/2 polar coding, converted into qubit superposition states, and transmitted through a 2x2 MIMO system with varied diversity schemes. At the receiver, a quantum decoder reconstructs the classical information, followed by polar decoding to retrieve the original image data. Our approach achieves notable improvements in image quality, with Peak Signal-to-Noise Ratio (PSNR) up to 58.27 dB for JPEG and 64.72 dB for HEIF, and Structural Similarity Index Measure (SSIM) up to 0.9994 for JPEG and 0.9999 for HEIF, outperforming classical systems, especially under low Signal-to-Noise Ratio (SNR) conditions, demonstrating the system’s enhanced ability to maintain image quality in noisy channels. These findings highlight the promise of quantum superposition-based media transmission to set new standards in reliable, high-fidelity communication for next-generation systems.
Quantum communication leverages the principles of quantum mechanics, such as superposition and entanglement, for inherently secure data transmission that can detect any eavesdropping attempt. This research addresses the limitations of classical encryption by proposing a hybrid Quantum Key Distribution (QKD) protocol that integrates the Bennett & Brassard 1984 Protocol(BB84) and Scarani-Acín-Ribordy-Gisin 2004 Protocol(SARG04) protocols. The primary objective is to enhance resilience against advanced threats such as Photon Number Splitting (PNS) and collective attacks, which are significant vulnerabilities in standard QKD implementations. The quantum channel is modeled using Qiskit Aer's noise framework, incorporating fiber attenuation (0.1−0.25dB/km), depolarization (1−5%), and detector dark counts (0.01−0.03probability), varied across 10 rounds. A simulation spanning 10 rounds evaluated key metrics, including Quantum Bit Error Rate (QBER), photon loss, and final key entropy. The results demonstrate the protocol's robustness, achieving a 0 % QBER in 50 % of the trials, representing a significant improvement in secure key generation. The average QBER across all rounds was 12.5 %, which is well below the 11 % theoretical threshold for secure communication. The highest QBER recorded was5 0 %in Round 02, where high depolarization and an eavesdropping attempt were simulated. The work's findings indicate that the hybrid BB84-SARG04 protocol significantly enhances the security and reliability of quantum communication.
Classical cryptography methods are becoming susceptible to quantum attacks like those implemented by Shor and Grover algorithms and can break RSA and symmetric-key encryption. Traditional communication channels are also susceptible to interception and even modification of the signal that causes data confidentiality to be compromised. In order to overcome these limitations, this paper proposes a three-layer quantum-hybrid communication framework, which integrates entanglement-based QKD, multi-channel redundancy, and steganographic hiding. The framework improves the security with an entanglement-assisted BB84-based protocol, the reliability with the help of multi-channel qubit transmission, and covert transmission with LSB/DCT-image embedding. The framework is developed and implemented as a simulator in Python using Qiskit, NumPy, and OpenCV and showed better Bit Error Rate (BER), SSIM, fidelity and security strength than classical systems. The proposed architecture mitigates key vulnerabilities in cryptographic strength, transmission stability, and communication detectability, providing a robust foundation for quantum-resilient and covert communication.
Quantum image transmission over noisy communication channels remains a challenge due to the fragility of quantum states and their susceptibility to channel impairments. Existing quantum encoding schemes often exhibit limited noise resilience, while advanced approaches introduce computational and implementation complexity. To address these limitations, this paper proposes a circular polarization-based quantum encoding framework for image transmission over error-prone channels. In the proposed approach, source images are compressed and source-encoded using standard image coding formats, including the joint photographic experts group (JPEG) standard and the high-efficiency image file format (HEIF), and converted into classical bitstreams. The resulting bitstreams are protected using channel coding and mapped onto quantum states via circular polarization representations, where left- and right-hand circularly polarized states encode binary information. The encoded quantum states are transmitted over noisy quantum channels to model channel impairments. At the receiver, appropriate quantum decoding and channel decoding operations are applied to recover the classical bitstream, followed by source decoding to reconstruct the image. The performance of the proposed framework is evaluated using image quality metrics, including peak signal-to-noise ratio (PSNR), structural similarity index measure (SSIM), and universal quality index (UQI). Simulation results demonstrate that the proposed circular polarization-based encoding scheme outperforms existing quantum image encoding techniques, achieving channel SNR gains of 4 dB over state-of-the-art Hadamard-based encoding and 3 dB over frequency-domain quantum encoding methods under severe noise conditions. These results indicate that circular polarization-based quantum encoding provides improved noise robustness and reconstruction fidelity for practical quantum image transmission systems.
Quantum Key Distribution (QKD) is increasingly recognized as a robust solution to the vulnerabilities posed by quantum computing to classical encryption systems. This paper presents a comprehensive investigation of the BB84 protocol, the foundational QKD scheme, through simulated quantum communication using IBM’s Qiskit framework. The study models quantum key exchange under both ideal and adversarial conditions, including channel noise and intercept-resend attacks. The Quantum Bit Error Rate (QBER) was measured as a function of noise intensity and eavesdropping, confirming that QBER increases predictably in compromised channels. A threshold of 11% QBER was used to determine the viability of secure key generation. Final key retention rates were analyzed across multiple channel scenarios, revealing BB84’s sensitivity to both photon loss and adversarial interference.\n\nSecurity vulnerabilities such as photon-number-splitting and detector blinding were assessed, and countermeasures including decoy-state protocols and authenticated classical channels were proposed. Four key performance graphs were generated to visualize system behavior under realistic operational conditions. The results support BB84’s theoretical advantage in ensuring information-theoretic security while acknowledging real-world limitations in transmission range and hardware reliability. The paper concludes by addressing future improvements in QKD systems, including satellite-based distribution, quantum repeaters, and device-independent implementations. Through simulation-driven analysis, this study validates BB84 as a practical defense against quantum-enabled attacks and underscores the need for continued development and standardization in post-quantum cryptographic infrastructure.