Controlled Secure Direct Communication Research Articles

Passive attack to the controlled secure direct communication with seven-qubit entangled states protocol

It is found that the controlled quantum secure direct communication (CQSDC) based on a seven-qubit entangled state protocol [S. K. Wang, X. W. Zha and H. Wu, Int. J. Theor. Phys. 57, 48 (2018)] can be passively attacked. That is to say, this protocol has the security loophole of information leakage. To be specific, the first bit of the sender’s two-bit message can be deduced by an attacker Eve according to the first and the third bits of Alice’s announcement and the first bit of the controller Charlie’s announcement. Then, a way to fix this loophole is discussed.

Controlled Secure Direct Communication Protocol via the Three-qubit Partially Entangled Set of States

In this paper, we first re-examine the previous protocol of controlled quantum secure direct communication of Zhang et al.’s scheme, which was found insecure under two kinds of attacks, fake entangled particles attack and disentanglement attack. Then, by changing the party of the preparation of cluster states and using unitary operations, we present an improved protocol which can avoid these two kinds of attacks. Moreover, the protocol is proposed using the three-qubit partially entangled set of states. It is more efficient by only using three particles rather than four or even more to transmit one bit secret information. Given our using state is much easier to prepare for multiqubit states and our protocol needs less measurement resource, it makes this protocol more convenient from an applied point of view.

Semi-quantum communication: protocols for key agreement, controlled secure direct communication and dialogue

Semi-quantum protocols that allow some of the users to remain classical are proposed for a large class of problems associated with secure communication and secure multiparty computation. Specifically, first time semi-quantum protocols are proposed for key agreement, controlled deterministic secure communication and dialogue, and it is shown that the semi-quantum protocols for controlled deterministic secure communication and dialogue can be reduced to semi-quantum protocols for e-commerce and private comparison (socialist millionaire problem), respectively. Complementing with the earlier proposed semi-quantum schemes for key distribution, secret sharing and deterministic secure communication, set of schemes proposed here and subsequent discussions have established that almost every secure communication and computation tasks that can be performed using fully quantum protocols can also be performed in semi-quantum manner. Further, it addresses a fundamental question in context of a large number problems- how much quantumness is (how many quantum parties are) required to perform a specific secure communication task? Some of the proposed schemes are completely orthogonal-state-based, and thus, fundamentally different from the existing semi-quantum schemes that are conjugate-coding-based. Security, efficiency and applicability of the proposed schemes have been discussed with appropriate importance.

Controlled Secure Direct Communication with Seven-Qubit Entangled States

In this paper, a new controlled secure direct communication protocol based on a maximally seven-qubit entangled state is proposed. the outcomes of measurement is performed by the sender and the controller, the receiver can obtain different secret messages in a deterministic way with unit successful probability.In this scheme,by using entanglement swapping, no qubits carrying secret messages are transmitted.Therefore, the protocol is completely secure.

Controlled Secure Direct Communication with Six-Qubit Entangled States

We propose an experimentally feasible scheme for implementing controlled quantum secure direct communication by using six-qubit entangled states. According to the results measured by the sender and the controller, the receiver can obtain different secret messages in a deterministic way with unit successful probability. In our scheme, the information-carrying qubits do not need to be transmitted over the public channel. Therefore, the scheme is determinate and secure.

Cryptanalysis and improvement of controlled secure direct communication

This paper points out that, due to a flaw in the sender's encoding, the receiver in Gao et al.'s controlled quantum secret direct communication (CQSDC) protocol [Chin. Phys. 14 (2005), No. 5, p. 893] can reveal the whole secret message without permission from the controller. An improvement is proposed to avoid this flaw.

Multipartite entanglement preparation and quantum communication with atomic ensembles

We propose an experimentally feasible scheme to generate Greenberger-Horne-Zeilinger type of maximal entanglement among three atomic ensembles, and show one of the applications, controlled secure direct communication. The scheme involves laser manipulation of atomic ensembles, quarter- and half-wave plates, beam splitters, polarizing beam splitters, and single-photon detectors, which are within the reach of current experimental technology.