Quantum computation has seen rapid progress in the past years. Due to implementation complexity and cost, cloud-based quantum computing is strongly believed to be the most feasible framework for individual users. Universal blind quantum computing (UBQC) provides the protocol for secure delegation of arbitrary quantum computations and has received significant attention. However, one of the major challenges in UBQC is a secure and reliable transmission of a quantum state over a long distance. Herein, we improve the efficiency of UBQC using alternative photon sources. Our analysis shows that a heralded single-photon source can significantly improve the transmitted distance of UBQC and a modified coherent source can reduce the required transmitted number of pulses. Furthermore, we study the finite-data-size effect, which is a crucial for real-world applications. Our proposed scheme can be a promising alternative for the future development of UBQC.
Quantum computation has seen rapid progress in the past years. Due to implementation complexity and cost, cloud-based quantum computing is strongly believed to be the most feasible framework for individual users. Universal blind quantum computing (UBQC) provides the protocol for secure delegation of arbitrary quantum computations and has received significant attention. However, one of the major challenges in UBQC is a secure and reliable transmission of a quantum state over a long distance. Herein, we improve the efficiency of UBQC using alternative photon sources. Our analysis shows that a heralded single-photon source can significantly improve the transmitted distance of UBQC and a modified coherent source can reduce the required transmitted number of pulses. Furthermore, we study the finite-data-size effect, which is a crucial for real-world applications. Our proposed scheme can be a promising alternative for the future development of UBQC.
Blind quantum computation is a scheme that adds unconditional security to cloud quantum computation. In the protocol proposed by Broadbent, Fitzsimons, and Kashefi, the ability to prepare and transmit a single qubit is required for a user (client) who uses a quantum computer remotely. In case a weak coherent pulse is used as a pseudo-single-photon source, however, we must introduce decoy states, owing to the inherent risk of transmitting multiple photons. In this paper, we demonstrate that by using a heralded single-photon source and a probabilistic photon number resolving detector we can gain a higher blind state generation efficiency and longer access distance, owing to noise reduction on account of the heralding signal.
The universal blind quantum computation (UBQC) protocol [A. Broadbent, J. Fitzsimons, and E. Kashefi, in Proceedings of the 50th Annual IEEE Symposiumon Foundations of Computer Science (IEEE Computer Society, Los Alamitos, CA, USA, 2009), pp. 517-526.] allows a client to perform quantum computation on a remote server. In an ideal setting, perfect privacy is guaranteed if the client is capable of producing specific, randomly chosen single qubit states. While from a theoretical point of view, this may constitute the lowest possible quantum requirement, from a pragmatic point of view, generation of such states to be sent along long distances can never be achieved perfectly. We introduce the concept of ϵ blindness for UBQC, in analogy to the concept of ϵ security developed for other cryptographic protocols, allowing us to characterize the robustness and security properties of the protocol under possible imperfections. We also present a remote blind single qubit preparation protocol with weak coherent pulses for the client to prepare, in a delegated fashion, quantum states arbitrarily close to perfect random single qubit states. This allows us to efficiently achieve ϵ-blind UBQC for any ϵ>0, even if the channel between the client and the server is arbitrarily lossy.
Blind quantum computation (BQC) is one of the most promising alternatives to solve the shortage of quantum resources in the implementation of quantum computations. However, in most reported studies on decoy-state BQCs, the source intensities are actively modulated, which, unfortunately, results in side-channel leakage and undermines system security. In this paper, we present a passive decoy-state BQC scheme with a heralded single-photon source that circumvents this problem skillfully, improving system security. Moreover, simulation results show that our passive scheme can even outperform other active schemes in the generation efficiency of blind states when using state-of-the-art equipment.
Blind quantum computation (BQC) is a recent proposition in which a computation is performed on a server by a client in a manner that the server is kept blind about the input, the algorithm and the output of the computation. This model possesses a natural security, which makes it suitable for applications where privacy matters. In this paper we propose a framework for BQC which can be implemented by circuit models as well as measurement-based models of quantum computation. It is based on gate teleportation, a process in which by storing one-qubit gates in entangled pairs one can apply it later via teleportation. We elaborate on examples of such universal BQC (UBQC) protocols. Specially, we elaborate on UBQC for correlation-space measurement-based quantum computation.
Abstract Blind quantum computation (BQC) allows a client without enough quantum technologies to delegate her quantum computation to a remote quantum server, while keeping her input, output and algorithm secure. In this paper, we propose a universal single-server and almost-classical-client BQC protocol. In this protocol, the client interfaces with only one server and the only ability of the client required is to get particles from the trusted center and forward them to the server. We present an analysis of this protocol and modify it to a universal single-server and fully-classical-client BQC protocol by improving the ability of the trusted center. Based on our protocols and recent works, a new ‘Cloud + Certificate Authority (CA)’ style is proposed for the BQC.
Quantum computing has seen tremendous progress in the past years. However, due to limitations in scalability of quantum technologies, it seems that we are far from constructing universal quantum computers for everyday users. A more feasible solution is the delegation of computation to powerful quantum servers on the network. This solution was proposed in previous studies of Blind Quantum Computation, with guarantees for both the secrecy of the input and of the computation being performed. In this work, we further develop this idea of computing over encrypted data, to propose a multiparty delegated quantum computing protocol in the measurement-based quantum computing framework.