Quantum message exchanging network using entanglement swapping and decoy photons (original) (raw)

Quantum secure direct communication by using GHZ states and entanglement swapping

Journal of Physics B: Atomic, Molecular and Optical Physics, 2006

We present a three-party quantum secure direct communication protocol by using Greenberg-Horne-Zeilinger (GHZ) states and entanglement swapping. The proposed scheme realizes authorized parties' secure exchange of their respective secret messages simultaneously and directly in a set of devices. We show that the scheme is secure against eavesdropper's commonly used attacks. We also generalize the protocol to the N-party case by using N-partite GHZ states. Quantum secure communication along a physical channel is doubtless one of the most attractive perspectives related to the latest developments of quantum physics. Based on physical laws instead of mathematical complexities, correspondence with perfect security could be guaranteed over an insecure channel in Vernam's sense of one-time pad, which is known as quantum cryptography. The pioneering work of Bennett and Brassard [1] showed how to exploit quantum resources for cryptographic purposes. Conventionally, the problem is referred to as quantum key distribution (QKD). Since then, a variety of quantum secure communication protocols have been proposed (for a review see [2]). Although the methods used in these schemes are various, all of them allow for a secret generation of random keys through which legitimate users can accomplish a thoroughly private communication. Recently, a new concept in quantum cryptography, quantum secure direct communication (QSDC) has been proposed [3-13], which permits confidential messages to be communicated directly without first establishing random keys to encrypt them. In [4], Boström and Felbinger proposed a ping-pong protocol for private communication, in which the encoded bit can be decoded directly in each respective transmission run, thus it can realize QSDC

Two-way quantum communication: 'secure quantum information exchange

Journal of Physics B-atomic Molecular and Optical Physics, 2011

In this paper, we present a new idea of two-way quantum communication called 'secure quantum information exchange' (SQIE). If there are two arbitrary unknown quantum states |ξrangIA and |ηrangIB, initially with Alice and Bob, respectively, then SQIE protocol leads to the simultaneous exchange of these states between Alice and Bob with the aid of the special kind of six-qubit entangled (SSE) state and classical assistance of the third party, Charlie. The term 'secure' signifies the fact that SQIE protocol either faithfully exchanges the unknown quantum states proceeding in a prescribed way or, in case of any irregularity, the process generates no results. For experimental realization of the SQIE protocol, we have suggested an efficient scheme for generating SSE states using the interaction between highly detuned Λ-type three-level atoms and the optical coherent field. By theoretical calculations, we found that SSE states of almost unit fidelity with perfect success rates for appreciable mean photon numbers (Fav >= 0.999 for |α|2 >= 1.5) can be generated by our scheme. Further, we have discussed possible experimental imperfections, such as atomic-radiative time, cavity damping time, atom-cavity interaction time, and the efficiency of discrimination between the coherent field and the vacuum state shows that our SQIE protocol is within the reach of technology presently available.

Quantum Based Networks: Analysis of Quantum Teleportation Protocol and Entanglement Swapping (Workshop Paper)

2019

In this paper we consider the quantum teleportation and entanglement swapping protocols used in quantum based networks for passing information between a sender and receiver. For the teleportation protocol we observe and identify relationships that exist between Einstein-Podolsky-Rosen (EPR) Bell states employed as quantum resources, measured sender values and the gates employed at the receiver side. For the entanglement swapping protocol we consider input and output EPR states and the relationship between the two. We include a review of the concepts and our findings from the analysis carried out.

Deterministic secure direct communication using GHZ states and swapping quantum entanglement

Journal of Physics A-mathematical and General, 2005

We present a deterministic secure direct communication scheme via entanglement swapping, where a set of ordered maximally entangled three-particle states (GHZ states), initially shared by three spatially separated parties, Alice, Bob and Charlie, functions as a quantum information channel. After ensuring the safety of the quantum channel, Alice and Bob apply a series local operations on their respective particles according to the tripartite stipulation and the secret message they both want to send to Charlie. By three Alice, Bob and Charlie's Bell measurement results, Charlie is able to infer the secret messages directly. The secret messages are faithfully transmitted from Alice and Bob to Charlie via initially shared pairs of GHZ states without revealing any information to a potential eavesdropper. Since there is not a transmission of the qubits carrying the secret message between any two of them in the public channel, it is completely secure for direct secret communication if perfect quantum channel is used.

Secure Communications Using Quantum Cryptography

Photonic Quantum …, 1997

The secure distribution of the secret random bit sequences known as "key" material, is an essential precursor to their use for the encryption and decryption of confidential communications. Quantum cryptography is an emerging technology for secure key distribution with single-photon transmissions: Heisenberg's uncertainty principle ensures that an adversary can neither successfully tap the key transmissions, nor evade detection (eavesdropping raises the key error rate above a threshold value). We have developed experimental quantum cryptography systems based on the transmission of non-orthogonal single-photon states to generate shared key material over multi-kilometer optical fiber paths and over line-of-sight links. In both cases, key material is built up using the transmission of a single-photon per bit of an initial secret random sequence. A quantum-mechanically random subset of this sequence is identified, becoming the key material after a data reconciliation stage with the sender. In our optical fiber experiment we have performed quantum key distribution over 24-km of underground optical fiber using single-photon interference states, demonstrating that secure, real-time key generation over "open" multi-km node-to-node optical fiber communications links is possible. We have also constructed a quantum key distribution system for free-space, line-of-sight transmissions using single-photon polarization states, which is currently undergoing laboratory testing.

Implementation of Secure Quantum Protocol using Multiple Photons for Communication

The paper presents the implementation of a quantum cryptography protocol for secure communication between servers in the cloud. As computing power increases, classical cryptography and key management schemes based on computational complexity become increasingly susceptible to brute force and cryptanalytic attacks. Current implementations of quantum cryptography are based on the BB84 protocol, which is susceptible to siphoning attacks on the multiple photons emitted by practical laser sources. The three-stage protocol, whose implementation is described in this paper, is a departure from conventional practice and it obviates some of the known vulnerabilities of the current implementations of quantum cryptography. This paper presents an implementation of the three-stage quantum communication protocol in free-space. To the best of the authors' knowledge, this is the first implementation of a quantum protocol where multiple photons can be used for secure communication.

Secret key sharing using entanglement swapping and remote preparation of quantum state

IEEE Long Island Systems, Applications and Technology (LISAT) Conference 2014, 2014

In this paper we propose a new algorithm for secret key sharing by utilizing quantum entanglement swapping and remote preparation of quantum state. This algorithm is used when two parties do not share an Einstein-Podolsky-Rosen (EPR) pair but one wishes to transmit a secret key to the other. In order to successfully accomplish this process, a third party who shares an EPR pair with both parties will help them build a new EPR pair. The new EPR pair will be used between the sender and the receiver to remotely prepare a quantum state. This process will provide a secure way to share secret keys between the two parties who do not share EPR pairs. Furthermore, the process doesn't require sending any physical quantum state, instead the sender prepares a known state and sends only one classical bit to the receiver to help build an intended quantum state.

Two-Way Quantum Communication: `Secure Quantum Information Exchange'-II. Generalization to Arbitrary Number of Qubits

2011

In this paper, we generalize the secure quantum information exchange (SQIE) protocol, originally proposed by the authors [J. Phys. B: At. Mol. Opt. Phys. 44 (2011) 115504] for secure exchange of one qubit information with each of Alice and Bob, to the case of secure exchange of quantum information of arbitrary qubits with Alice and Bob. We also discuss security of the original and generalized SQIE protocols with respect to the number of qubits with controller, Charlie.