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Multi-hop teleportation is a quantum teleportation scheme for transferring quantum states on a large scale. In this paper, a new multi-hop teleportation protocol is investigated for transferring arbitrary N-qubit states between M-neighbor nodes. In this scheme, intermediate nodes are connected with each other by symmetric entangled Bell states as quantum channels. First, one-hop teleportation of single-qubit, two-qubit and N-qubit states are introduced, then this method is generalized to two-hop and multi-hop teleportation for N-qubit. Also, we calculate the efficiency of this scheme.

We present an arbitrated quantum blind signature scheme by entanglement swapping, which is simplified from the preparation and operation of the quantum states. Compared with the classical blind signature, quantum arbitration has added the role of the third party arbitration, so the structure of the protocol has changed. The traceability depends on the third party arbitration, and the blind operation and the signature operation can be carried out simultaneously.

In the paper [Mod. Phys. Lett. B31 (2017) 1750150], Yin et al. proposed a semi-quantum secret sharing scheme by using Bell states. We find that the proposed scheme cannot finish the quantum secret sharing task. In addition, we also find that the proposed scheme has a security loophole, that is, it will not be detected that the dishonest participant, Charlie attacks on the quantum channel.

Two tripartite schemes with a pair of Bell states and a Greenberger–Horne–Zeilinger (GHZ) state respectively have been proposed recently by Zhang and Cheung for remotely sharing two restricted sets of operations in a deterministic manner [J. Phys. B 44 (2011) 165508]. In this paper, we generalize the schemes with the same quantum channels so that another six restricted sets of operations can be shared deterministically, too. Features about scheme security, sharer symmetry, fulfillment determinacy and experimental feasibility are discussed and revealed. Moreover, some comparisons are also made from the aspects of quantum and classical resource consumption, necessary operation complexity and efficiency.

A new concept of bidirectional quantum operation teleportation (BQOT) is proposed, which is essentially a union of the idea of quantum operation teleportation (QOT) and bidirectional quantum teleportation (QT). This means that Alice can transmit an unknown single-qubit unitary operation $U_A$ on the remote Bob’s quantum system; and at the same time, Bob can also transmit an arbitrary single-qubit unitary operation $U_B$ on Alice’s quantum system. In this paper, we present three BQOT schemes via different quantum channels. Furthermore, using these quantum channels, we investigate the BQOT in noisy environments, such as phase-damping noise and amplitude-damping noise. We considered the influence of the noises on the process of these three BQOT protocols through analytical derivation of the fidelity. Moreover, these three schemes are amply compared with each other from five aspects, i.e. quantum resource consumption, operation complexity, classical resource consumption, success probability and efficiency. It is found that these schemes can be realized deterministically and the first scheme is better than the other two schemes.

In this paper, we design a novel quantum secret information equal exchange protocol, which implements the equal exchange of secret information between the two parties with the help of semi-trusted third party (TP). In the protocol, EPR pairs prepared by the TP are, respectively, distributed to both the communication parties. Then, the two parties perform Pauli operation on each particle and return the new particles to TP, respectively. TP measures each new pair with Bell basis and announces the measurement results. Both parties deduce the secret information of each other according to the result of announcement by TP. Finally, the security analysis shows that this protocol solves the problem about equal exchange of secret information between two parties and verifies the security of semi-trusted TPs. It proves that the protocol can effectively resist glitch attacks, intercept retransmission attacks and entanglement attack.

A four-party single-qubit operation sharing scheme is put forward by utilizing the Bell and Yeo–Chua product state in an entanglement structure as the composite quantum channel. Four features of the scheme are discussed and confirmed, including its determinacy, symmetry, and security as well as the scheme experimental feasibility. Moreover, some concrete comparisons between our present scheme and a previous scheme [H. Xing et al., Quantum Inf. Process. 13 (2014) 1553] are made from the aspects of quantum and classical resource consumption, necessary operation complexity, and intrinsic efficiency. It is found that our present scheme is more superior than that one. In addition, the essential reason why the employed state in the entanglement structure is applicable for sharing an arbitrary single-qubit operation among four parties is revealed via deep analyses. With respect to the essential reason, the capacity of the product state in quantum operation sharing (QOS) is consequently shown by simple presenting the corresponding schemes with the state in other entanglement structures.

In this paper, we introduce a protocol for mutual sharing of known quantum information between different parties. We show that it is possible to exchange known non-maximally entangled Bell states between three parties through a protocol by use of a multipartite entangled state. The scheme is overseen by a controller.

A three-party quantum secret sharing scheme is proposed, in which the dealer uses the d-dimensional Bell state to distribute the secret, the participants perform the single-particle measurements to get their shares, and the dealer performs the Bell-basis measurements to check the eavesdropping. The main merit of our scheme is that the participants only need to measure the particles in one basis. Compared to the existing schemes in which the participants need to measure the particles in two bases, our scheme will be more practical.