Quantum secure direct communication over the collective amplitude damping channel

Abstract

An efficient quantum secure direct communication protocol is presented over the amplitude damping channel. The protocol encodes logical bits in two-qubit noiseless states, and so it can function over a quantum channel subjected to collective amplitude damping. The feature of this protocol is that the sender encodes the secret directly on the quantum states, the receiver decodes the secret by performing determinate measurements, and there is no basis mismatch. The transmission's safety is ensured by the nonorthogonality of the noiseless states traveling forward and backward on the quantum channel. Moreover, we construct the efficient quantum circuits to implement channel encoding and information encoding by means of primitive operations in quantum computation.quantum secure direct communication, amplitude damping, quantum cryptography Quantum cryptography [1] is one of the most remarkable applications of quantum information. Since the pioneering work [2] , various protocols based on different quantum features are proposed, such as quantum key distribution (QKD) [3,4] , quantum secret sharing (QSS) [5,6] , quantum secure direct communication (QSDC) [7,8] and so on. QSDC is a novel branch which allows that the secret is transmitted between users directly without creating a private key in advance. As it is useful in some urgent circumstances, many efforts have been made on the research of QSDC [9][10][11][12][13][14][15][16][17][18][19][20][21] . For example, Deng et al. proposed four criteria for secure QSDC [12] and gave two secure QSDC protocols [10,12] , Cai et al. presented two efficient QSDC schemes with entangled states [9] and single qubit [11] , respectively.In contrast to classical cryptography, the security of quantum cryptography is guaranteed by the principles of quantum mechanics, and therefore the unconditional security can be achieved. Properly speaking, according to quantum physics principles, Eve's eavesdropping will inevitably disturb the carrier states and induce errors in the process of checking eavesdropping. Higher error rate results in lower information transmission rate, and once it becomes too large, no secure message can be transmitted and the communications will have to abort. Therefore, building a viable quantum cryptographic system depends on ensuring that the error rate is low. However in practice, quantum states are very fragile and easily destroyed by decoherence due to unwanted coupling with the environment, and errors are induced in the eavesdropping detection inevitably. It has been one of the major obstacles to implementing quantum cryptography protocols in real physical systems. To solve the effects of such interactions, some strategies, such as quantum error correction code [22,23] and quantum error-rejection code [24][25][26][27] have been proposed.Considering the specific types of coupling with the

A Quantum Private Comparison Protocol with Splitting Information Carriers

“…Therefore, some well known attacks such as intercept-resend attack [11,34,49], the measure-resend attack, the entangle-measure attack can be detected via the checking mechanism [44][45][46]. Moreover, since there are round trip transmissions, the eavesdropper may take Tro-jan horse attack and invisible-photon attack [34,39,40]. Concretely, he/she may prepare in-visible photons or fake photons and split them into two wave packets by their own beam splitter BS.…”

“…Since Bennett and Brassard presented the first quantum cryptographic protocol [1] in 1984, quantum cryptography has developed quickly. Many kinds of quantum cryptographic protocols have been proposed to solve various different security problems, such as quantum key distribution (QKD) [1][2][3][4][5][6][7][8][9], quantum secure direct communication (QSDC) [10][11][12][13][14][15][16][17][18], quantum secret sharing (QSS) [19][20][21][22][23] and quantum key agreement (QKA) [24][25][26][27]. As another branch of quantum cryptography, quantum private comparison (QPC) also attracts much attention.…”

Quantum Direct Communication

“…During the communication process, if Alice wants to send a k bit binary sequence of message M. She first picks a [[2m, 2k, t]] one-party-QECC that are used to correct the errors in the second transmission. There are k logical EPR pairs in the code pairs and she encodes M to her halves of the second-level logical qubits in the code pairs by applying (30) on the 2i-th logical qubit where the i-th bit of M is 1. Actually Alice is able to apply this local operation.…”

High-Capacity Quantum Secure Direct Communication with Single Photons in Both Polarization and Spatial-Mode Degrees of Freedom

“…In 2007, Li et al [25] proposed a QSDC with quantum encryption. In 2009, Qin et al [26] proposed a QSDC protocol under a collective damp noise and Gu et al [27] proposed a QSDC protocol under a collective noise.…”