Abstract Quantum key distribution is a practically implementable cryptographic communication methodology from the hardware and software point of view. It is an information‐theoretic secure method for transmitting keys to remote partners practicing quantum communication. After examining various protocols from the most basic on, BBM92, DPSK, SARG04 and MDI (Measurement Device Independent) protocols are described in view of targeting the longest possible communication distance with the highest secret key bitrate. How any protocol can be optimized with respect to distance is discussed by analyzing the various steps impacting hardware and software that are developed, starting from the underlying assumptions proper to every protocol and ending with the corresponding performance in each case.
Abstract Quantum key distribution is a practically implementable cryptographic communication methodology from the hardware and software point of view. It is an information‐theoretic secure method for transmitting keys to remote partners practicing quantum communication. After examining various protocols from the most basic on, BBM92, DPSK, SARG04 and MDI (Measurement Device Independent) protocols are described in view of targeting the longest possible communication distance with the highest secret key bitrate. How any protocol can be optimized with respect to distance is discussed by analyzing the various steps impacting hardware and software that are developed, starting from the underlying assumptions proper to every protocol and ending with the corresponding performance in each case.
Quantum Key Distribution is a practically implementable information-theoretic secure method for transmitting keys to remote partners performing quantum communication. After examining various protocols from the simplest such as QC and BB84 we move on to describe BBM92, DPSK, SARG04 and finally MDI from the largest possible communication distance and highest secret key bitrate. We discuss how any protocol can be optimized by reviewing the various steps and underlying assumptions proper to every protocol with the corresponding consequence in each case.
Quantum Key Distribution (QKD) which is the name of cryptography in quantum environment act as the highest developed area in quantum communication and computing technology (QCIT). \n \nQKD is inventive technology which utilize the laws of quantum to create a cryptographic share key to make the communication system secure. The unique feature of QKD assures eavesdropping detectable during quantum communications which is fascinating for a high-level secure environment.Most of the traditional cryptographic methods which we use currently are based on mathematical scheme or Computational complexity theory which are not completely safe. Using quantum cryptography has been achieved extensive steps in communication security establishment. As the information Unit has been changed from “bit” to Quantum bit (Qubit), a new element has been offered that can guarantee the shared information confidentiality between parties. The confidentiality of system is established via exchanging a secret key through a channel of quantum, the key which we use for encrypting the shared data. This structure has quantum integration which has been developed by physics law and techniques of cryptography. \n \nThis thesis has proposed a modified version of QKD protocol, this new protocol will generate a cryptographic share key for a more efficient, lower cost and secure communication between two parties (sender and Receiver). This new protocol principal is similar to BBM92, but the source of photon moved to sender instead of third-party photon generator, following steps will be executed in this Experiment: \n \n•\tObserve different categories protocols of QKD in details \n•\tThe Quantum Mechanics Visualisation Project (QuVis) is the simulation software that has been used for implementing the proposed protocol [BB84 with spin] among the other three (BBM92, B92 and BB84). \n•\tProbability ratio of error will be tested and compared for all protocols, for this experiment 100 to 5000 photons will be sent. \n \nBy Analysing collected data in this experiment, it will be determined which one of this four protocols lead the detecting of eavesdropping. Simulation software accomplishes the value of error key probability which receiver can use and should not pass over the range limit of 0.25 & 0.5.
Quantum computing poses significant threats to conventional cryptographic techniques such as RSA and AES, motivating the need for quantum secure communication methods. Quantum Key Distribution (QKD) offers information theoretic security based on fundamental quantum principles. This paper presents a simulation-based analysis of well-known QKD protocols, namely BB84, B92, and E91, using the IBM Qiskit framework. Realistic quantum channel effects, including noise, decoherence, and eavesdropping, are modeled to evaluate protocol performance. Key metrics such as error rate, secret key generation, and security characteristics are analyzed and compared. The study highlights practical challenges in QKD implementation, including hardware limitations and channel losses, and discusses insights toward scalable and robust quantum communication systems. The results support the feasibility of QKD as a promising solution for secure communication in the quantum era.
The measurement device independent (MDI) Quantum Key Distribution (QKD) is a practically implementable method for transmitting secret keys between respective partners performing quantum communication. SARG04 (Scarani-Acìn-Ribordy-Gisin 2004) is a protocol tailored to struggle against photon number splitting (PNS) attacks by eavesdroppers and its MDI-QKD version is reviewed and optimized from secret key bitrate versus communication distance point of view. We consider the effect of several important factors such as error correction function, dark counting parameter and quantum efficiency in order to achieve the largest key bitrate versus longest communication distance.
This report reviews two quantum key distribution (QKD) protocols: the BB84 protocol and the measurement device independent (MDI) QKD protocol. The goal of this report is to recreate the security proof of the BB84 protocol, to generate the secret key rate for a practical application of the BB84 protocol, both with and without decoy states, and to review the MDI-QKD protocol and look at the advantages it has for practical QKD. The proof security of the BB84 protocol is done by designing an equivalent theoretical protocol and proving its security by bounding the information of the eavesdropper to an exponentially small number. The best distance over which secret key rate can be generated with the practical model of the BB84 protocol that is presented in this report, is 165 km. This is achieved by employing decoy states and is more than three times as far as the model can achieve without decoy states, which gave a distance of 52 km at best. The zero distance key rate of the model with decoy states is R = 1.21 · 10-2 bits per pulse (bpp), at best. This is an order of magnitude larger than R =1.02 · 10-3 bpp, which is what the model without decoy states could produce. The decoy state method is therefore an improvement for practical QKD. By reviewing the MDI-QKD protocol it can be concluded that because it eliminates the measurement device side channels, it is very useful for practical QKD, since it makes security analysis simpler and more precise. It also necessarily employs decoy states, which improves the secret key rate. MDI-QKD therefore is a promising protocol to use for future quantum communications.
This chapter introduces Quantum Key Distribution (QKD), a key cryptographic technology that employs quantum mechanics to enhance communication security. Central to QKD is its use of quantum principles such as superposition, entanglement, and the no-cloning theorem, which collectively facilitate the generation of secure cryptographic keys. These keys are secure against both traditional cryptographic attacks and those posed by emerging quantum computing technologies. The chapter begins with a detailed introduction to the core concepts of QKD, explaining how it fundamentally differs from classical cryptographic methods by ensuring security based on the laws of physics rather than computational complexity. It traces the historical evolution of QKD, from early theoretical formulations to its current implementations and the development of key protocols like the BB84, which marked a significant milestone in practical QKD applications. As the discussion progresses, the chapter explores various sophisticated QKD protocols, including E91, decoy-state, and Measurement Device Independent (MDI) protocols. Each protocol is analysed for its operational mechanics, security features, and the specific challenges it addresses in protecting data against quantum threats. The technical complexities and requirements for implementing these protocols in real-world scenarios are also examined, showing their potential and limitations for extending secure communication networks. Moreover, the chapter evaluates the practical challenges associated with QKD, such as managing transmission distances, environmental susceptibilities, and the infrastructural demands of deploying quantum networks. It concludes by highlighting the future directions of QKD, underscoring its growing integration into critical global communication infrastructures, and its significant potential to revolutionize data security in the quantum age. This chapter presents the significance of QKD in modern cryptography, demonstrating its evolution from a conceptual framework to a fundamental technology set to counteract the challenges of quantum decryption. Through this approach, the chapter demonstrates the critical role of QKD in fortifying the foundations of secure communications worldwide.