Abstract Quantum key distribution (QKD) introduces a fun- damentally different paradigm for secure communication by leveraging the physical laws of quantum mechanics rather than computational assumptions. This work presents an expanded simulation-grounded analysis of BB84 under intercept-resend attacks, emphasizing quantum bit error rate (QBER), adver- sarial disturbance, and integration into modern cybersecurity architectures.
Abstract Quantum key distribution (QKD) introduces a fun- damentally different paradigm for secure communication by leveraging the physical laws of quantum mechanics rather than computational assumptions. This work presents an expanded simulation-grounded analysis of BB84 under intercept-resend attacks, emphasizing quantum bit error rate (QBER), adver- sarial disturbance, and integration into modern cybersecurity architectures.
The BB84 protocol is fundamental to quantum-secure communications, yet its extension to multi-receiver networks remains underexplored. This study addresses this gap by implementing a dual-receiver BB84 framework in Qiskit to evaluate security against intercept–resend and photon-number-splitting (PNS) attacks. Our methodology incorporates weak coherent pulses and realistic channel imperfections. Key findings show that intercept–resend attacks induce a detectable (~25%) increase in QBER, while PNS attacks allow a 100% gain in eavesdropper information with less than 2.5% QBER—revealing a critical vulnerability, which highlights the importance of a true single-photon source. The findings emphasize the suitability of BB84 for multiparty QKD scenarios, either as a decoy-state mechanism for enhanced eavesdropping detection or as a direct secure communication protocol.
As quantum computing threatens classical cryptography like RSA via Shor's algorithm, Quantum Key Distribution (QKD)—especially BB84—offers physics-based security. BB84 leverages quantum principles: Heisenberg Uncertainty, No-Cloning Theorem, and superposition, shifting from math complexity to unbreakable physical laws using polarized photons for key exchange. The protocol detects eavesdropping through Quantum Bit Error Rate (QBER), showing 25% errors in Intercept-Resend attacks. Key challenges like Photon Number Splitting (PNS) attacks are addressed via decoy states. Compared to B92 and E91, BB84 balances feasibility and security best. Despite issues like signal loss, BB84 provides provably secure communication, restoring trust in a post-quantum world.
Quantum Key Distribution (QKD) provides an innovative approach for secure communication by utilizing the principles of quantum mechanics. Among various QKD protocols, the BB84 protocol remains the most widely studied and implemented due to its simplicity and theoretical security guarantees. However, practical implementations of BB84 are vulnerable to several eavesdropping attacks and channel imperfections. This paper presents a comprehensive study on the detection and analysis of eavesdropping attacks in the BB84 protocol. The work focuses on common attacks such as intercept-resend attack, photon-number splitting attack, Trojan horse attack, and phase-covariant cloning attack. The effect of these attacks on Quantum Bit Error Rate (QBER) is analyzed in detail. Simulation-based observations are discussed to demonstrate how QBER increases under malicious interference. The study further explores statistical methods for detecting eavesdropping and examines practical countermeasures including decoy states, privacy amplification, and error correction techniques. The paper concludes that BB84 remains robust against eavesdropping when proper detection and mitigation mechanisms are employed.
Abstract Secure military communications depend on the confidentiality of exchanged cryptographic keys across command centers, satellite links, and classified order transmission. Classical key-distribution protocols rely on computational hardness assumptions that provide no intrinsic mechanism for detecting interception; an adversary who copies transmitted ciphertext leaves no physical trace. Quantum Key Distribution (QKD), and specifically the BB84 protocol, replaces this assumption with a physical guarantee derived from quantum mechanics: any attempt to measure an unknown quantum state necessarily disturbs it, rendering interception statistically detectable. This study implements the BB84 protocol at the circuit level — qubit state preparation, basis selection, interception modeling, and measurement — and validates its central security property, the Quantum Bit Error Rate (QBER) signature of eavesdropping, in two stages: (1) a noiseless statevector simulation using the PKTron quantum computing framework over ten independent trials per condition, and (2) hardware execution on IBM Quantum's ibm_fez superconducting processor. In simulation, the average QBER without an eavesdropper was 0.000, and with a full intercept-resend attack was 0.248, closely matching the theoretical prediction of 0.25. On real hardware, the undisturbed channel returned QBER = 0.000 (19 sifted bits) and the eavesdropped channel returned QBER = 0.261 (23 sifted bits), in close agreement with both theory and the simulated baseline. These results provide a reproducible, two-platform validation of the eavesdropper-detection mechanism that underlies the security claims made for QKD-protected communications. This study validates the cryptographic detection primitive only; it does not constitute a deployed secure communications system, and extending these results to operational command, satellite, or classified-order channels requires physical single-photon transmission hardware, authenticated classical channels, and full key-management infrastructure outside the scope of this work.
Quantum Key Distribution (QKD) provides information-theoretic security by exploiting the principles of quantum mechanics. Among QKD protocols, the BB84 scheme remains the most widely adopted for both theoretical research and practical implementation. A critical parameter determining the reliability and security of BB84 is the Quantum Bit Error Rate (QBER), which quantifies errors in the sifted key arising from channel noise or potential eavesdropping. This paper presents a systematic review and analysis of QBER within the BB84 protocol, examining its calculation, statistical estimation methods, and role in detecting eavesdropping activity. Simulation results, corroborated by reported experimental observations, reveal a near-linear relationship between eavesdropping intensity and QBER, with values approaching 25% under full intercept-resend attacks. Four confidence interval estimation methods, Wald, Wilson, Clopper-Pearson, and Hoeffding's inequality, are compared for robust QBER analysis in finite-key scenarios. Protocol enhancements, including decoy-state methods, hybrid cryptographic models, and quantum-resistant authentication, are discussed as mechanisms to mitigate errors and strengthen resilience across fiber, free-space, underwater, and satellite QKD systems. Open challenges in distinguishing noise-induced errors from malicious eavesdropping, and the role of adaptive error correction and machine-learning-assisted QBER estimation in future quantum networks, are identified as key directions for further research.
The rapid progress of quantum computing demands secure communication protocols which are beyond classical cryptographic techniques. This necessity of Quantum Key Distribution (QKD) is met by providing security relying on the fundamental laws of quantum mechanics. In the work presented, the BB84 protocol is implemented using Qiskit platform provided by IBM. The performance is analyzed for both the ideal channel conditions and an intercept–resend eavesdropping scenario studying its security behavior and performance. 100% key agreement is observed with a QBER of 0% for the BB84 protocol executed under the ideal condition. When an eavesdropper is introduced, the QBER increases significantly, ranging from 16% to 38%, exceeding the acceptable security threshold of 11% and resulting in complete rejection of the generated key. Performance analysis carried out for key sizes between 100 and 1000 qubits shows that the execution time follows O(n) trend growing linearly. This simulation validates the correct operation of the BB84 protocol and demonstrates a detailed performance and security analysis of a QKD system using IBM Qiskit.