Modified BB84 Protocol Using CCD Technology

Secured Data Aggregation Scheduling in Ubiquitous sensor networks is a major research problem nowadays. Since the sensors communicate wirelessly, they are exposed to a high level of vulnerability from the intruders. Quantum key distribution is a technique that is used nowadays for providing security. Though the secure keys are used for short distances only, it offers many advantages over traditional methods in providing security. Quantum key distribution adopts many methods like entanglement swapping and quantum teleportation. Reversible logic gates like CNOT, Toffoli, and Fredkin are proved to offer many advantages in quantum computing. Also a very little research is carried to provide security to the nodes in ubiquitous sensor networks using quantum cryptography so as to maximize the throughput and utilize the hardware resources effectively. Hence in this paper, we propose an intrusion detection policy for security to sensor nodes using quantum cryptography. The proposed protocol monitors the communication between sensor nodes and uses a simple policy to detect the malicious nodes. In our detection policy we adopted an EPR-pair allocation scheme in terms of the quantum gates like Toffoli and Feynman called SwapGate.

Quantum cryptography, and especially quantum key distribution (QKD), is steadily progressing to become a viable tool for cryptographic services. In recent years we have witnessed a dramatic increase in the secure bit rate of QKD, as well as its extension to ever longer fibre- and air-based links and the emergence of metro-scale trusted networks. In the foreseeable future even global-scale communications may be possible using quantum repeaters or Earth–satellite links. A handful of start-ups and some bigger companies are already active in the field. The launch of an initiative to form industrial standards for QKD, under the auspices of the European Telecommunication Standards Institute, described in the paper by Laenger and Lenhart in this Focus Issue, can be taken as a sign of the growing commercial interest.

Physical implementations of quantum key distribution (QKD) protocols, like the Bennett-Brassard (BB84), are forced to use attenuated coherent quantum states, because the sources of single photon states are not functional yet for QKD applications. However, when using attenuated coherent states, the relatively high rate of multi-photonic pulses introduces vulnerabilities that can be exploited by the photon number splitting (PNS) attack to brake the quantum key. Some QKD protocols have been developed to be resistant to the PNS attack, like the decoy method, but those define a single photonic gain in the quantum channel. To overcome this limitation, we have developed a new QKD protocol, called ack-QKD, which is resistant to the PNS attack. Even more, it uses attenuated quantum states, but defines two interleaved photonic quantum flows to detect the eavesdropper activity by means of the quantum photonic error gain (QPEG) or the quantum bit error rate (QBER). The physical implementation of the ack-QKD is similar to the well-known BB84 protocol.

This chapter discusses quantum information science (QIS), quantum key distribution (QKD), and quantum teleportation. The new field of QIS encompasses several overlapping subdisciplines: quantum computing, quantum key distribution (also known as quantum cryptography), and quantum metrology (the measurement of small parameters and weak forces with ultra-high precision). In QIS, bits of information are encoded in quantum states, which themselves can be in superposition states and/or entanglement states. Generically, the 0 and 1 quantum bits are represented as qubits (quantum bits). QKD, or quantum cryptography, is a completely secure method of secret communication, and will remain so even if a quantum computer becomes available. Quantum teleportation is one of the more exotic features to have emerged from the field of QIS. It refers to the ability to transfer an unknown quantum state from one location to another, possibly very distant, location by using quantum entanglement.

Covert communication methods are used in the communication with high security level. When it turns to quantum communication, covertness is also an important concern which is firstly discussed by Arrazola and Scarani (Phys Rev Lett, 117:250503, 2016). To make quantum key distribution (QKD) protocol more suitable in the scenarios need high security, we propose a covert QKD protocol with decoy-state method in this paper. The secure key rate and covertness of the covert decoy-state QKD are proved. We compare the performance of the covert decoy-state QKD with those of the original decoy-state QKD and covert QKD without decoy states in numerical simulations. It shows that (1) the covert decoy-state QKD can have a performance comparable to the original decoy-state QKD protocol besides its covertness; (2) the covert decoy-state QKD can have a considerable improvement of transmission distance over covert QKD without decoy states at the cost of a small change of covertness parameter. Furthermore, the statistical fluctuation due to the finite length of data is also taken into account based on the Gaussian analysis method.

Quantum key distribution (QKD) can provide point-to-point information-theoretic secure key services for two connected users. In fact, the development of QKD networks needs more focus from the scientific community in order to broaden the service scale of QKD technology to deliver end-to-end secure key services. Of course, some recent efforts have been made to develop secure communication protocols based on QKD. However, due to the limited key generation capability of QKD devices, high quantum secure key utilization is the major concern for QKD networks. Since traditional routing techniques do not account for the state of quantum secure keys on links, applying them in QKD networks directly will result in underutilization of quantum secure keys. Therefore, an efficient routing protocol for QKD networks, especially for large-scale QKD networks, is desperately needed. In this study, an efficient routing protocol based on optimized link-state routing, namely QOLSR, is proposed for QKD networks. QOLSR considerably improves quantum key utilization in QKD networks through link-state awareness and path optimization. Simulation results demonstrate the validity and efficiency of the proposed QOLSR routing protocol. Most importantly, with the growth of communication traffic, the benefit becomes even more apparent.

We develop a novel key routing algorithm for quantum key distribution (QKD) networks that utilizes a distribution of keys between remote nodes, i.e., not directly connected by a QKD link, through multiple non-overlapping paths. This approach focuses on the security of a QKD network by minimizing potential vulnerabilities associated with individual trusted nodes. The algorithm ensures a balanced allocation of the workload across the QKD network links, while aiming for the target key generation rate between directly connected and remote nodes. We present the results of testing the algorithm on two QKD network models consisting of 6 and 10 nodes. The testing demonstrates the ability of the algorithm to distribute secure keys among the nodes of the network in an all-to-all manner, ensuring that the information-theoretic security of the keys between remote nodes is maintained even when one of the trusted nodes is compromised. These results highlight the potential of the algorithm to improve the performance of QKD networks.

formula omitted] quantum channels are sufficient for Multi-user Quantum Key Distribution protocol between [formula omitted] users

The security of quantum cryptography protocols after a quantum key distribution (QKD) session is formulated in terms of proximity between two situations: quantum states corresponding to real and ideal situations after QKD. The measure of proximity is the trace distance. It is more reasonable to formulate security directly in terms of the smallness of probability of successive guessing of keys by an eavesdropper after an arbitrary number of QKD sessions. There is a fundamental question the answer to which is a priori very unobvious: Is the security criterion in terms of the proximity of the real and ideal situations for a single QKD session sufficient to guarantee the security of keys in terms of the smallness of probability of guessing of keys by the eavesdropper after an arbitrary number of QKD sessions? It has been shown that the answer to this question is positive.

Chapter 6 - Quantum key distribution

Quantum correlations or entanglement is a basic ingredient for many applications of quantum information theory.One important application using quantum entanglement exploits the correlation nature of entangled photon states is quantum key distribution, which is proven unbreakable in principle and provides the highest possible security that is impossible in classical information theory. However, generating entangled photon pairs is not a simple task -- only approximately one out of a million pump photons decay into a signal and idler photon pair. This low rate of entangled photon pairs is further reduced by the overhead required in order for the rectification of the inevitable errors due to channel imperfections or caused by potential eavesdroppers. As a consequence, quantum key distribution suffers from a low bit rate, which is in the order of hundreds to thousands bits per second or below. On the other hand, the classical public key distribution does not impose a tight limit on the transmission rate. However, it is subject to the risks of eavesdroppers sitting in the middle of the insecure channel. In this paper, we propose a hybrid key distribution method which uses public key distribution method to generate a raw key, and then uses entanglement assisted communication to modify the raw key by inserting a number of quantum bits in the raw key. Building upon the foundation of the unconditional security of quantum key distribution, we use the privacy amplification to make the affection of inserted bits expand to a whole key. Our quantum entanglement assisted key distribution scheme greatly improves the efficiency of key distribution while without compromising the level of security achievable by quantum cryptography.

<sec>Measurement-device-independent quantum key distribution (MDI-QKD) protocol can effectively resist all possible attacks targeting the measurement devices in a quantum key distribution (QKD) system, thus exhibiting high security. However, due to the protocol’s high sensitivity to channel attenuation, its key generation rate and transmission distance are significantly limited in practical applications.</sec><sec>To improve the performance of MDI-QKD, researchers have proposed quantum-memory (QM)-assisted MDI-QKD protocol, which has enhanced the protocol's performance to a certain extent. Nevertheless, under finite-size conditions where the total number of transmitted pulses is limited, accurately estimating the relevant statistical parameters is still a challenge. As a result, existing QM-assisted MDI-QKD schemes still encounters issues such as low key rates and limited secure transmission distances.</sec><sec>To solve these problems, this work proposes a novel improved finite-size QM-assisted MDI-QKD protocol. By utilizing quantum memories to temporarily store early-arriving pulses and release them synchronously, the protocol effectively reduces the influence caused by channel asymmetry. Additionally, the protocol introduces a four-intensity decoy-state method to improve the estimation accuracy of single-photon components. Meanwhile, to mitigate the influence of finite-length effects on QM schemes, the proposed protocol combines a collective constraint model and a double-scanning algorithm to jointly estimate scanning error counts and vacuum-related counts. This approach enhances the estimation accuracy of the single-photon detection rate and phase error rate under finite-size conditions, thereby significantly improving the secure key rate of the MDI-QKD system.</sec><sec>Simulation results show that under the same experimental conditions, compared with the existing QM-assisted three-intensity decoy-state MDI-QKD protocol and the four-intensity decoy-state MDI-QKD protocol based on Heralded Single-photon Source (HSPS), the proposed protocol extends the secure transmission distance by more than 30 km and 100 km, respectively. This proves that under the same parameter settings, the proposed scheme exhibits significant advantages in both key rate and secure transmission distance. Therefore, this research provides important theoretical references and valuable benchmarks for developing long-distance, high-security quantum communication networks.</sec>

The proposed article is devoted to the investigation of quantum key distribution protocols. The idiosyncrasy of this theme lies within the truth that present day strategies of key distribution, which utilize classical computing at their center, have critical downsides, in contrast to quantum key distribution. This issue concerns all sorts of calculations and frameworks for scrambling mystery data, both symmetric encryption with a private key and deviated encryption with an open key. A case is that in a communication channel ensured by quantum key distribution, it is conceivable to distinguish an interceptor between two legitimate organize substances utilizing the standards laid down in quantum material science at the starting of the final century. Standards and hypotheses such as the Heisenberg guideline, quantum trap, superposition, quantum teleportation, and the no-cloning hypothesis. The field of ponder of this theme may be a promising and quickly creating zone within the field of data security and data security. There are as of now made commercial items with the usage of a few of the quantum key dispersion conventions. Numerous of the made items are utilized in different circles of human movement. The significance of applying quantum key distribution conventions beneath perfect conditions without taking into consideration blunders within the frame of quantum clamor is analyzed. The usage of three quantum key distribution conventions is illustrated, as well as the comes about of the appearance of keys and the likelihood of event of each of them. The purpose of the article is pointed at analyzing and investigating quantum key distribution conventions. The article examines the points of interest and impediments of the BB84, B92, and E91 quantum key distribution conventions.

Quantum key distribution (QKD) provides the opportunity to deliver unconditional communication security. The most robust version of QKD relies on quantum entanglement. Very recently, ubiquitous deployment of such entanglement-based QKD over large distances has moved closer to reality, as verified by quantum entanglement distribution from a low Earth orbit satellite. We will demonstrate that this robust form of QKD via space will require a renewed focus on short-block length error-correcting codes in order to facilitate the reconciliation phase of the key distribution. Focusing on discrete variable QKD and adopting the low data rates consistent with measured entanglement distribution from space, we quantify the benefits of state-of-the-art short- block length codes in the context of device- independent QKD. Our results highlight the trade- off between the attainable key throughput vs the communication latency encountered in space-based implementations of this ultra-secure technology.

As an important support for quantum communication, quantum key distribution (QKD) networks have achieved a relatively mature level of development, and they face higher requirements for multi-user end-to-end networking capabilities. Thus, QKD networks need an effective management plane to control and coordinate with the QKD resources. As a promising technology, software defined networking (SDN) can separate the control and management of QKD networks from the actual forwarding of the quantum keys. This paper systematically introduces QKD networks enabled by SDN, by elaborating on its overall architecture, related interfaces, and protocols. Then, three-use cases are provided as important paradigms with their corresponding schemes and simulation performances.