Quantum key distribution (QKD) is a secure communication protocol that uses quantum bits (qubits) to ensure the security of key exchange between two entities (Alice and Bob). Their shared qubits may suffer from errors due to noise and eavesdropping in the quantum channels. After the QKD key agreement phase, Alice's key may not be different from Bob's key. Therefore, we need key verification to deal with the inconsistent qubits (i.e. the wrong qubits at receiver end). This key verification process is also known as information reconciliation. Recently, Kurt et al. proposed a reconciliation in QKD (RQKD) by using the polynomial consistency property. In this paper, we propose an enhanced RQKD (ERQKD) to improve key verification. Our method is still based on polynomial consistency, but uses the properties of consistency in a different way to obtain better key verification efficiency.
Quantum key distribution (QKD) is a secure communication protocol that uses quantum bits (qubits) to ensure the security of key exchange between two entities (Alice and Bob). Their shared qubits may suffer from errors due to noise and eavesdropping in the quantum channels. After the QKD key agreement phase, Alice's key may not be different from Bob's key. Therefore, we need key verification to deal with the inconsistent qubits (i.e. the wrong qubits at receiver end). This key verification process is also known as information reconciliation. Recently, Kurt et al. proposed a reconciliation in QKD (RQKD) by using the polynomial consistency property. In this paper, we propose an enhanced RQKD (ERQKD) to improve key verification. Our method is still based on polynomial consistency, but uses the properties of consistency in a different way to obtain better key verification efficiency.
Quantum communication uses photons to transmit quantum bits (qubits) over long distances. By using this quantum technology, quantum key distribution (QKD), a secure communication protocol, ensures the security of encryption key exchange. Due to noise and eavesdropping in the quantum channel, errors can occur in the shared qubits after QKD key agreement phase. Therefore, we need a key verification phase to deal with inconsistent qubits (i.e. the wrong qubits at the receiving end). This key verification is also called information reconciliation. Recently, some reconciliation algorithms in QKD (RQKD) using polynomial consistency have been proposed. These RQKDs use the consistency property to find the correct polynomial (converted from the qubits) and then check the correctness of other qubits based on this polynomial to achieve reconciliation. All previous consistency-based RQKDs required such an extra step to check the correctness of other qubits after finding the correct polynomial. In this paper, we propose Enhanced RQKD (ERQKD), which uses consistency in a new way to improve key verification efficiency without requiring additional checking steps. Theoretical analysis and experiments indeed show that our ERQKD outperforms the two previous RQKDs.
Quantum Key Distribution (QKD) could share a secret key between two distant nodes Alice and Bob. In the presence of an eavesdropper and noisy channel, Alice’s key may not be the same as Bob’s key. Thus, QKD protocol has to provide not only the distribution in key agreement phase but also the integrity in key verification phase. Error reconciliation is often used in QKD to share identical keys between Alice and Bob in key verification phase. Recently, Kurt et al. introduce a reconciliation algorithm for QKD (RQKD) to prevent error propagation in some previous reconciliation algorithms. Kurt et al.’s RQKD is a block-wise operation, and uses polynomial interpolation for reconciliation. However, if the x-axis values of polynomials are the same the blocks are removed. In this paper, we propose an enhanced RQKD (ERQKD) to deal with this weakness. When using polynomial-interpolation approach for reconciliation, our ERQKD without deleting block improves the efficiency of sharing qubits.
Abstract In quantum cryptography, secret communications are delivered through a quantum channel. One of the most important breakthroughs in quantum cryptography has been the quantum key distribution (QKD). This process enables two distant parties to share secure communications based on physical laws. However, eavesdroppers can still interrupt the communication. To overcome this, we propose a different way to detect the presence of Eve through the polynomial interpolation technique. This technique also allows us for key verification. This approach prevents the receiver as well as the intruder from discovering the sender’s fundamental basis. To fully utilize IBM quantum computers’ quantum computing capabilities, this paper attempts to show % error against alpha (strength of eavesdropping) and the impact of noise on the success probability of the desired key bits. Furthermore, the success probability under depolarizing noise is explained for different qubit counts. In the enhanced QKD protocol, using polynomial interpolation for reconciliation shows a 50% probability of successful key generation. This is even when the noise is increased to the maximum capacity.
Quantum cryptography is the study of delivering secret communications across a quantum channel. Recently, Quantum Key Distribution (QKD) has been recognized as the most important breakthrough in quantum cryptography. This process facilitates two distant parties to share secure communications based on physical laws. The BB84 protocol was developed in 1984 and remains the most widely used among BB92, Ekert91, COW, and SARG04 protocols. However the practical security of QKD with imperfect devices have been widely discussed, and there are many ways to guarantee that generated key by QKD still provides unconditional security. This paper proposed a novel method that allows users to communicate while generating the secure keys as well as securing the transmission without any leakage of the data. In this approach sender will never reveal her basis, hence neither the receiver nor the intruder will get knowledge of the fundamental basis.Further to detect Eve, polynomial interpolation is also used as a key verification technique. In order to fully utilize the quantum computing capabilities provided by IBM quantum computers, the protocol is executed using the Qiskit backend for 45 qubits. This article discusses a plot of % error against alpha (strength of eavesdropping). As a result, different types of noise have been included, and the success probability of the desired key bits has been determined. Furthermore, the success probability under depolarizing noise is explained for different qubit counts.Last but not least, even when the applied noise is increased to maximum capacity, a 50% probability of successful key generation is still observed in an experiment.
Sharing a secret key between two physically separated nodes, Alice and Bob, is possible through the use of quantum key distribution (QKD) techniques. In the presence of an eavesdropper, Alice's key may not be identical with Bob's key, due to the characteristics of a quantum channel. To obtain identical keys at Alice and Bob, we propose a block-based key verification protocol that relies on Newton's polynomial interpolation. As the nodes solely share random numbers and indices of the removed blocks, no information is revealed about the secret message, at a cost of higher computational complexity. The error propagation through the key verification process is prevented by the characteristics of the proposed approach.
Quantum cryptography is essentially the quantum key distribution (QKD). In the context of QKD, one from two partners (Alice) generates and sends a sequence of qubits through a private quantum channel to another partner (Bob) and Bob receives the sequence and measures the state of each qubit. After the quantum transmission stage, Alice and Bob have almost identical qubit sequences. The erros are due to physical imperfections in the channel and presence of an eavesdropper. The next stage in QKD is key reconciliation (i.e. finding and correcting discrepancies between Alice's string and that of Bob). This reconciliation can be done by public discussion. Let us suppose there is a secret quantum channel between Alice and Bob through which Alice transmits a n-bit string A=(A1, A2,...,An)ε{0,1}n. Then Bob receives a n-bit string B=(B1, B2,...,Bn)ε{0,1)n. The string B differs from A due to the presence of noise and eavesdropper in the channel. One can estimate the bit error probability in the channel. For example, Bob can choose a random subset from his string and send it to Alice in public. Then Alice compares the received string with her corresponding subset and calculates the total number of protocol steps. The cascade scheme uses the interaction over the public channel to correct the secret strings by dividing them into the blocks of a fixed length. The length is determined from the bit error probability. A simple interactive routine is applied in each of these blocks. An error found in some block results in some action with other blocks. It is important to optimize the error-finding routines in standalone blocks as well as to organize the effective constrution of blocks with the object of protocol benchmark, information leakage and number of interactions between partners.