We attempt to propose the first orthogonal-state-based protocols of measurement-device-independent quantum secure direct communication and quantum dialogue employing single basis, i.e., Bell basis as decoy qubits for eavesdropping detection. Orthogonal-state-based protocols are inherently distinct from conventional conjugate-coding protocols, offering unconditional security derived from the duality and monogamy of entanglement. Notably, these orthogonal-state-based protocols demonstrate improved performance over conjugate-coding based protocols under certain noisy environments, highlighting the significance of selecting the best basis choice of decoy qubits for secure quantum communication under collective noise. Furthermore, we rigorously analyze the security of the proposed protocols against various eavesdropping strategies, including intercept-and-resend attack, entangle-and-measure attack, information leakage attack, flip attack, and disturbance or modification attack. Our findings also show that, with appropriate modifications, the proposed orthogonal-state-based measurement-device-independent quantum secure direct communication protocol can be transformed into orthogonal-state-based measurement-device-independent versions of quantum key distribution protocols, expanding their applicability. Our protocols leverage fundamentally distinct resources to close the security loopholes linked to measurement devices, while also effectively doubling the distance for secure direct message transmission compared to traditional quantum communication methods.
We attempt to propose the first orthogonal-state-based protocols of measurement-device-independent quantum secure direct communication and quantum dialogue employing single basis, i.e., Bell basis as decoy qubits for eavesdropping detection. Orthogonal-state-based protocols are inherently distinct from conventional conjugate-coding protocols, offering unconditional security derived from the duality and monogamy of entanglement. Notably, these orthogonal-state-based protocols demonstrate improved performance over conjugate-coding based protocols under certain noisy environments, highlighting the significance of selecting the best basis choice of decoy qubits for secure quantum communication under collective noise. Furthermore, we rigorously analyze the security of the proposed protocols against various eavesdropping strategies, including intercept-and-resend attack, entangle-and-measure attack, information leakage attack, flip attack, and disturbance or modification attack. Our findings also show that, with appropriate modifications, the proposed orthogonal-state-based measurement-device-independent quantum secure direct communication protocol can be transformed into orthogonal-state-based measurement-device-independent versions of quantum key distribution protocols, expanding their applicability. Our protocols leverage fundamentally distinct resources to close the security loopholes linked to measurement devices, while also effectively doubling the distance for secure direct message transmission compared to traditional quantum communication methods.
Abstract We attempt to propose the first orthogonal-state-based protocols of measurement-device-independent quantum secure direct communication and quantum dialogue employing single basis, i.e., Bell basis as decoy qubits for eavesdropping detection. Orthogonal-state-based protocols are inherently distinct from conventional conjugate-coding protocols, offering unconditional security derived from the duality and monogamy of entanglement. Noise imposes a major challenge to the efficient implementation of these measurement-device-independent based secure direct quantum communication protocols. Notably, these orthogonal-state-based protocols demonstrate improved performance over conjugate-coding-based protocols under certain noisy environments, highlighting the significance of selecting the best basis choice of decoy qubits for secure quantum communication under collective noise. Further, we rigorously analyze the security of the proposed protocols against various eavesdropping strategies, including intercept-and-resend attack, entangle-and-measure attack, information leakage attack, flip attack, and disturbance or modification attack. Our findings also show that, with appropriate modifications, the proposed orthogonal-state-based measurement-device-independent quantum secure direct communication protocol can be transformed into orthogonal-state-based measurement-device-independent versions of quantum key distribution and quantum key negotiation protocols, expanding their applicability. Our protocols leverage fundamentally distinct resources to close the security loopholes linked to measurement devices, while also effectively doubling the distance for secure direct message transmission compared to traditional quantum secure direct communication protocols. Additionally, we calculate the efficiency of our proposed protocols and compare them with standard versions of measurement-device-independent quantum secure direct communication protocols. Ultimately, we discuss system and operational complexity of our proposed protocols in light of experimental elements and the processes.
Most quantum communication protocols like BB84 use non-orthogonal basis sets composed of orthogonal states, where an eavesdropper can access only 50% of the sender’s information. Thus, the overall eavesdropping rate becomes 25%, due to the same access rate of the receiver. This high error rate in a quantum channel provides an “Attack” sign to the system. However, the 25% attack to the quantum channel can no longer be effective if Eve can measure one conjugate variable without disturbing the other. Recently, such direct measurement techniques have been presented, and then most quantum communication protocols will be endangered eventually. Here we propose a direct measurement independent quantum communication (MIQC) protocol belongs to quantum secure direct communication (QSDC) systems. QSDC mostly relies on quantum entanglement and memories for direct message transfer, but it is more vulnerable due to direct information loss to Eve. Moreover, those QSDC protocols are not easy to implement and will become no longer of use if a direct measurement becomes possible. Our MIQC uses four conjugate variables composed of polarization and phase. To satisfy the measurement independence, we added two phase bases to the polarization-superposed single photons, where the phase selection is for random choices of spatially distinct quantum channels. Thus, Eve cannot know which path is chosen even if she can perfectly measure the encoded photon’s state. In our MIQC, Eve’s attack rate drops down to less than 1%, showing a measurement independent quantum communication protocol applicable to direct secure message transfers.
Quantum entanglement is a fundamental physical resource that enables a range of information-processing tasks with no efficient solution on classical computers. In this paper, we construct a class of general maximum entangled states by parameterizing the coefficients of Bell states. By calculating, we obtain the local unitary operations required to realize the mutual transformation of the constructed states, analogous to Pauli operators acting on one particle of a Bell state. Interestingly, the local unitary operations on the two particles of Bell states are identical, whereas for the constructed states, they must differ in certain cases. To explore the potential applications of these maximum entangled states and the obtained local unitary operations, we design a class of measurement-device-independent quantum secure direct communication protocols based on entanglement swapping. In the class of designed protocols, entanglement swapping is realized between a constructed maximum entangled state and a Bell state. We demonstrate that the class of designed protocols have no information leakage and can resist intercept-and-resend attacks, measure-resend attacks, and collective attacks. In addition, the unconditional security of the class of designed protocols is proved. We believe that the constructed maximum entangled states and the obtained local unitary operations may find applications in other quantum information-processing fields.
Quantum key distribution is proven to offer unconditional security in communication between two remote users with ideal source and detection. Unfortunately, ideal devices never exist in practice and device imperfections have become the targets of various attacks. By developing up-conversion single-photon detectors with high efficiency and low noise, we faithfully demonstrate the measurement-device-independent quantum-key-distribution protocol, which is immune to all hacking strategies on detection. Meanwhile, we employ the decoy-state method to defend attacks on a nonideal source. By assuming a trusted source scenario, our practical system, which generates more than a 25 kbit secure key over a 50 km fiber link, serves as a stepping stone in the quest for unconditionally secure communications with realistic devices.
Quantum secure direct communication enables a direct message exchange over a quantum channel without any key generation in advance. Here we present a feasible protocol for long-distance measurement-device–independent quantum secure direct communication. The secure distance is increased by using ancillary entangled photon-pair sources and relay nodes. Meanwhile, its security is independent from measurement devices, which eliminates the potential loophole for eavesdropping in the detection systems. Moreover, this protocol can be implemented with linear optical devices and single-photon detectors.
Recently, measurement-device-independent quantum secure direct communication schemes were proposed by Niu et al. (Sci.Bull. 63:1345, 2018) and Zhou et al. (Sci. China-Phys. Mech. Astron. 63:230362, 2020). Inspired by their ideas, in this paper, a measurement-device-independent quantum dialogue protocol based on entanglement is designed and proved to be secure. The advantage of this scheme is that it can not only allow two communicators transmit secret message each other, making the application scenarios more extensive, but also eliminate all the security loopholes related to the measurement device and information leakage. In terms of experimental implementation, the scheme mainly involves the preparation of entangled states, the preparation of single photon, quantum storage, Bell measurement and other technologies, all of which are mature at present, therefore, the scheme is feasible by using the current technologies.