Quantum Secure Direct Communication Based on Four-Qubit Cluster States

Controlled Secure Direct Communication with Six-Qubit Entangled States

“…First Alice prepares a quantum state + ab , and performs the Bell-state measurements on the qubit pairs (a, 1) and (b, 2), and then sends the result to Bob and Charlie. At last, Bob makes the Bell-state measurements on the qubits (3,4) and Charlie performs two single-qubit measurements on the qubits (5, 6), and compare the qubits parts (a, 1), (b, 2), (3,4) and (5,6) outcomes results to get the information 00 from Alice. The theory and all of results are shown as follows: …”

“…The process as follows: Eve intercepts the sequence P i 56 in which Alice sends to Charlie, and then Alice prepares other ordered sequence of six-qubit entangled states and sends the sub-sequence of qubit pairs (5,6) to Charlie. Fortunately, this case can be found by checking of Charlie and Alice.…”

“…Since the first standard QKD scheme was proposed in 1984, QKD has attracted widespread attention and progressed quickly [1][2][3][4][5][6] Quantum secure direct communication (QSDC) is another branch of quantum cryptography. Since the first QSDC scheme based on the basis of the QKD was presented [7] QSDC have been investigated extensively [8][9][10][11].…”

Remotely Sharing a Single-Qubit Operation via a Six-Qubit Entangled State

“…Entanglement is considered to be an important resource for applications of quantum information, such as quantum teleportation [1][2][3][4][5][6][7], quantum secure direct communication [8][9][10][11][12][13][14], remote state preparation [15][16][17][18][19], quantum key distribution [20][21][22][23], and so on. In 2011, Zhang and Cheung [24] proposed the concept of quantum operation sharing (QOS).…”

Two Quantum Direct Communication Protocols Based on Quantum Search Algorithm

“…Deng et al [17] proposed a two-step QSDC protocol based on Bell states in 2004. Following the two-step QSDC and the Ping-Pong QSDC protocol, scholars have proposed many QSDC protocols based on single photons [21,22], Bell states [23], multi-particle quantum states [24][25][26] and high-dimension quantum states [27,28]. Long et al [15] reviewed the development of QSDC and DSQC, and presented the criteria for QSDC.…”