Security against simple eavesdropping attacks is demonstrated for a recently proposed quantum key distribution protocol which uses the Fibonacci recursion relation to enable high-capacity key generation with entangled photon pairs. No transmitted pairs need to be discarded in reconciliation; the only pairs not used for key generation are those used for security-checking. Although the proposed approach does not allow eavesdropper-induced errors to be detected on single trials, it can nevertheless reveal the eavesdropper's action on the quantum channel by detecting changes in the distribution of outcome probabilities over multiple trials, and can do so as well as the BB84 protocol. The mutual information shared by the participants is calculated and used to show that a secret key can always be distilled.
Security against simple eavesdropping attacks is demonstrated for a recently proposed quantum key distribution protocol which uses the Fibonacci recursion relation to enable high-capacity key generation with entangled photon pairs. No transmitted pairs need to be discarded in reconciliation; the only pairs not used for key generation are those used for security-checking. Although the proposed approach does not allow eavesdropper-induced errors to be detected on single trials, it can nevertheless reveal the eavesdropper's action on the quantum channel by detecting changes in the distribution of outcome probabilities over multiple trials, and can do so as well as the BB84 protocol. The mutual information shared by the participants is calculated and used to show that a secret key can always be distilled.
Quantum key distribution algorithms are considered secure because they leverage quantum phenomena to provide security. As such, eavesdroppers can be detected by analyzing the error rate in the shared key obtained by the parties performing the key exchange. Nevertheless, this paper developed and investigated a novel attack strategy capable of being undetected through error analysis of the shared key. Said attack entails an eavesdropper measuring the quantum channel (i.e., the channel used to transmit quantum particles between two parties) using a higher dimension than that used by the legitimate parties. By measuring a particle in a dimension that spans all possible states in a given quantum key distribution algorithm, the collapsed state of the measured particle should be undetectable when measured in the lower dimension. To analyze the proposed high-dimensional eavesdropping attack, the simulator Cirq was used to model the attack on BB84, a four-dimensional variant of BB84, and the Six-State Protocol. The results of these simulations show the efficiency of this attack, with an eavesdropper being undetectable through quantum bit error rate analysis in each algorithm This promotes the need for further analysis of the high-dimensional eavesdropping attack on physical hardware and other quantum key distribution algorithms
Data transmission has always been vulnerable to eavesdropping.Conventional cryptography has provided security in data communication, however it has some limitations when dealing with passive eavesdropping.Recently, the quantum mechanics has made a remarkable entry in the field of data communication.Now, it is possible to construct cryptographic communication systems which detect unauthorized eavesdropping and guarantee its prevention.Several protocols have been devised to implement such systems e.g., BB84, B92 and EPR.The famous BB84 protocol describes quantum encryption in terms of polarization states of a photon.The secret information is t ransmitted via secure quantum channel followed by a public conversation for verification and reconciliation.The B92 protocol is an extension of BB84 which shows how photons with non-orthogonal states can be used to distribute a secret key.The EPR protocol utilizes an entangled photon pair for encryption-one photon from this pair is transmitted towards the destination while keeping the other at the source; the destination photon describes the state of the source photon, failing to which confirms the intrusion.This paper presents a study of these protocols and a review on the recent developments in the field of secure quantum transmission.
Quantum cryptography and quantum key distribution (QKD) have been the most successful applications of quantum information processing, highlighting the unique capability of quantum mechanics, through the no-cloning theorem, to protect the security of shared encryption keys. Here we present a new and fundamentally different approach to high-capacity, high-efficiency QKD by exploiting interplay between cross-disciplinary ideas from quantum information and light scattering of aperiodic photonic media. The novelty of the proposed approach relies on a unique type of entangled-photon source and a new physical mechanism for efficiently sharing keys. The new source produces entangled photons with orbital angular momenta (OAM) randomly distributed among Fibonacci numbers. Combining entanglement with the mathematical properties of Fibonacci sequences leads to a new QKD protocol. This Fibonacci protocol is immune to photon-number-splitting attacks and allows secure generation of long keys from few photons. Unlike other protocols, reference frame alignment and active modulation of production and detection bases are unnecessary, since security does not require use of non-orthogonal polarization measurements.
A striking scheme called ``counterfactual quantum cryptography'' gives a conceptually new approach to accomplish the task of key distribution. It allows two legitimate parties to share a secret even though a particle carrying secret information is not, in fact, transmitted through the quantum channel. Since an eavesdropper cannot directly access the entire quantum system of each signal particle, the protocol seems to provide practical security advantages. However, here we propose an eavesdropping method which works on the scheme in a finite key scenario. We show that, for practical systems only generating a finite number of keys, the eavesdropping can obtain all of the secret information without being detected. We also present a improved protocol as a countermeasure against this attack.
Quantum cryptography is anticipated to drive substantial advancements in cybersecurity. The impending arrival of quantum cryptography compromises current encryption methods, possibly compromising the effectiveness of traditional key management-based security protocols. One fundamental Quantum Key Distribution (QKD) protocol, BB84, encounters challenges when operating with fewer Quantum bits (Qubits) and bases that only support up to 8 Qubits. This limitation weakens the system’s security, making brute force, intercept, and resend attacks less challenging. Consequently, this study proposes a method to enhance the security of the BB84 protocol, to reduce susceptibility to attacks and eavesdropping. The improved BB84 protocol utilizes 9, 12, and 16 quantum bits along with two, and three bases to significantly bolster security. This allows authorized parties to eliminate the use of compromised keys. Additionally, the study implements the E91 QKD protocol utilizing the Entanglement Pair Generation (EPR) method to produce secure keys. While the existing E91 protocol ensures security through Bell’s theorem and Bell’s inequality, it overlooks the impact of noise, leading to inaccuracies in eavesdropper detection. To address this, the study introduces an additional security measure. Whenever an eavesdropper attempts to measure the quantum state, the proposed E91 protocol collapses its state from$\vert 10\rangle to\vert 11\rangle ,settingthefirstQubitto\vert 1\rangle andtheotherQubitto\vert 0\rangle $, thus providing the eavesdropper with incorrect information, accompanied by a phase angle of$15\pi $/8. This leads to a misconception, preventing eavesdroppers from obtaining useful details about transferred quantum states. Additionally, considering that the proposed E91 protocol relies on entangled particles and utilizes double Qubit gates, which are inherently noisier than single Qubit gates and more susceptible to quantum decoherence, this study employs error mitigation techniques during the final measurement to predict outcomes more efficiently.
The quantum key distribution protocol BB84, published by C. H. Bennett and G. Brassard in 1984, describes how two spatially separated parties can generate a random bit string fully known only to them by transmission of single-qubit quantum states. Any attempt to eavesdrop on the protocol introduces disturbance which can be detected by the legitimate parties. In this Master's Thesis a novel modification to the BB84 protocol is analyzed. Instead of sending single particles one-by-one as in BB84, they are grouped and a non-local transformation is applied to each group before transmission. Each particle is sent to the intended receiver, always delaying the transmission until the receiver has acknowledged the previous particle on an authenticated classical channel, restricting eavesdropping to accessing the quantum transmission one particle at a time. Hence, an eavesdropper cannot undo the non-local transformation perfectly. Even if perfect cloning of quantum states was possible the state of the group could not be cloned. We calculate the maximal information on the established key provided by an intercept-resend attack and the induced disturbance for different transformations. We observe that it is possible to significantly reduce the eavesdropper's maximal information on the key--to one eighth of that in BB84 for a fixed, reasonable amount of disturbance. We also show that the individual access to the particles poses a fundamental restriction to the eavesdropper, and discuss a novel attack type against the proposed protocol.