Quantum key distribution (QKD) relies on randomness to exchange secret keys among the communicating parties. While ensuring the secrecy of the keys being distributed, independent randomness also causes to reduce the number of key bits that can be shared per quantum signal exchanged. Recently it was shown that it is possible to use pseudo-randomness in place of true randomness in the QKD without compromising the integrity of a QKD scheme. By the virtue of a short secret key — called a control key — shared among the key sharing parties, same pseudo-randomness can be generated at the transmitter and the receiver end that allow to obtain a higher key exchange rate. However, there are certain modifications which are necessary before pseudo-randomness can be safely employed in a QKD procedure. In this paper, we provide a modification of QKD schemes for a secure use with the control key. We modify the prepare-and-measure (BB84) type, and measurement-device independent protocols. We then verify the advantages of use of control key in terms of key rates for the modification of two QKD schemes.
Quantum key distribution (QKD) relies on randomness to exchange secret keys among the communicating parties. While ensuring the secrecy of the keys being distributed, independent randomness also causes to reduce the number of key bits that can be shared per quantum signal exchanged. Recently it was shown that it is possible to use pseudo-randomness in place of true randomness in the QKD without compromising the integrity of a QKD scheme. By the virtue of a short secret key — called a control key — shared among the key sharing parties, same pseudo-randomness can be generated at the transmitter and the receiver end that allow to obtain a higher key exchange rate. However, there are certain modifications which are necessary before pseudo-randomness can be safely employed in a QKD procedure. In this paper, we provide a modification of QKD schemes for a secure use with the control key. We modify the prepare-and-measure (BB84) type, and measurement-device independent protocols. We then verify the advantages of use of control key in terms of key rates for the modification of two QKD schemes.
Quantum key distribution (QKD) schemes rely on the randomness to exchange secret keys between two parties. A control key to generate the same (pseudo)-randomness for the key exchanging parties increases the key exchange rate. However, the use of pseudo-randomness where true randomness is required makes a classical system vulnerable to the known plain-text attack. Contrary to the belief of unavailability of this attack in QKD, we show that this attack is actually possible whenever a control key is employed. In this paper, we show that it is possible to make use of the uncertainty principle to not only avoid this attack, but also remove the hazards of photon-number splitting attack in quantum setting. We define the secrecy of control key based on the guessing probability, and propose a scheme to achieve this defined secrecy. We show the general applicability of our framework on the most common QKD schemes.
Abstract In the process of quantum key distribution (QKD), the communicating parties need to randomly determine quantum states and measurement bases. To ensure the security of key distribution, we aim to use true random sequences generated by true random number generators as the source of randomness. In practical systems, due to the difficulty of obtaining true random numbers, pseudo-random number generators are used instead. Although the random numbers generated by pseudo-random number generators are statistically random, meeting the requirements of uniform distribution and independence, they rely on an initial seed to generate corresponding pseudo-random sequences. Attackers may predict future elements from the initial elements of the random sequence, posing a security risk to quantum key distribution. This paper analyzes the problems existing in current pseudo-random number generators and proposes corresponding attack methods and applicable scenarios based on the vulnerabilities in the pseudo-random sequence generation process. Under certain conditions, it is possible to obtain the keys of the communicating parties with very low error rates, thus effectively attacking the quantum key system. This paper presents new requirements for the use of random numbers in quantum key systems, which can effectively guide the security evaluation of quantum key distribution protocols.
Quantum cryptography is a well-stated field within quantum applications where quantum information is used to set secure communications, authentication, and secret keys. Now used in quantum devices with those purposes, particularly Quantum Key Distribution (QKD), which proposes a secret key between two parties free of effective eavesdropping, at least at a higher level than classical cryptography. The best-known quantum protocol to securely share a secret key is the BB84 one. Other protocols have been proposed as adaptations of it. Most of them are based on the quantum indeterminacy for non-orthogonal quantum states. Their security is commonly based on the large length of the key. In the current work, a BB84-like procedure for QKD based on double quantum teleportation allows the sharing of the key statement using several parties. Thus, the quantum bits of information are assembled among three parties via entanglement, instead of travelling through a unique quantum channel as in the traditional protocol. Asymmetry in the double teleportation plus post-measurement retains the secrecy in the process. Despite requiring more complex control and resources, the procedure dramatically reduces the probability of success for an eavesdropper under individual attacks, because of the ignorance of the processing times in the procedure. Quantum Bit Error Rate remains in the acceptable threshold and it becomes configurable. The article depicts the double quantum teleportation procedure, the associated control to introduce the QKD scheme, the analysis of individual attacks performed by an eavesdropper, and a brief comparison with other protocols.
Quantum key distribution (QKD) is a provably secure way for two distant parties to establish a common secret key, which then can be used in a classical cryptographic scheme. Using quantum entanglement, one can reduce the necessary assumptions that the parties have to make about their devices, giving rise to device-independent QKD (DIQKD). However, in all existing protocols to date the parties need to have an initial (at least partially) random seed as a resource. In this work, we show that this requirement can be dropped. Using recent advances in the fields of randomness amplification and randomness expansion, we demonstrate that it is sufficient for the message the parties want to communicate to be (partially) unknown to the adversaries---an assumption without which any type of cryptography would be pointless to begin with. One party can use her secret message to locally generate a secret sequence of bits, which can then be openly used by herself and the other party in a DIQKD protocol. Hence our work reduces the requirements needed to perform secure DIQKD and establish safe communication.
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.
The traditional security system, which depends on asymmetric and symmetric key exchange protocol, is now under threat due to recent developments in quantum computing. In order to generate the safe key without storing the qubit by the sender or recipient trustworthy parties, a unique Quantum Key Distribution (QKD) protocol was presented. Four random classical bits coupled to generate a pair of bell states in any of the places {(1,2,3,4), (1,3,2,4) and (1,4,2,3)}. "n/2" groups were used to generate the raw key while the remaining groups were used to check for Eve. The flying bell states scatter into four separate bell states as a result of Eve's involvement in choosing the incorrect measurement basis, which causes entanglement swapping and its identification during communication. The sender will alter the key in accordance with the receiver's position preference because, in traditional communication, key receiving parties must announce the position information. Under the intercept-measure-resend attack, the trade-off between the key generating rate and disturbance is computed and security is examined. Circuit simulation is demonstrated graphically in IBM Quantum Lab and the proposed protocol is implemented.