Private quantum computation: an introduction to blind quantum computing and related protocols

Fitzsimons, Joseph F.

doi:10.1038/s41534-017-0025-3

Cited by 186 publications

(124 citation statements)

References 116 publications

(189 reference statements)

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“…Quantum information science holds the promise of providing novel capabilities and computational speedups for a host of problems related to computer science [1], secure communication [2][3][4][5][6], the simulation of physical systems [7,8], and distributed computation [9][10][11][12]. One quantum computing paradigm is measurement-based computing [13][14][15] with a highly entangled cluster state (figure 1).…”

Section: Introductionmentioning

confidence: 99%

Generation of arbitrary all-photonic graph states from quantum emitters

2019

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We present protocols to generate arbitrary photonic graph states from quantum emitters that are in principle deterministic. We focus primarily on two-dimensional cluster states of arbitrary size due to their importance for measurement-based quantum computing. Our protocols for these and many other types of two-dimensional graph states require a linear array of emitters in which each emitter can be controllably pumped, rotated about certain axes, and entangled with its nearest neighbors. We show that an error on one emitter produces a localized region of errors in the resulting graph state, where the size of the region is determined by the coordination number of the graph. We describe how these protocols can be implemented for different types of emitters, including trapped ions, quantum dots, and nitrogen-vacancy centers in diamond. is a 2×m cluster state, where m is the number of cycles. Schemes to create ladder-type cluster states using trapped ions have also been proposed [29]. However, for universal quantum computation, a larger twodimensional grid (n by m, with n, m?2) is needed; moreover, fault-tolerant universal computation requires a three-dimensional grid [30]. One interesting proposal to create a larger two-dimensional grid using feedback and atom-photon interactions in a cavity has been put forward [31]. However, this approach requires coupling the emitter to a chiral waveguide, which has yet to be demonstrated experimentally with high efficiency.In this paper, we propose an in-principle deterministic method to produce an arbitrary graph state that does not require photon-photon interactions. Instead, the entanglement is created between emitters and then transferred onto photons through optical pumping. This is similar to the idea presented in [28], although here, in addition to being able to create states corresponding to arbitrary graphs of any size, our scheme also allows for the entangling operations between emitters to occur after the photon pumping. Combined with heralding of the emission process, this allows one to perform the typically costly entangling operation only if there is a successful photon emission. Moreover, we show that, in a precise sense, our approach allows for the maximum possible delay in transferring the entanglement from the emitters onto the photons. Our protocol allows for arbitrary sized n by m clusters, given a linear array of n emitters, where each emitter can be entangled with its nearest neighbors. The operations required of the linear array are only a single two-emitter entangling gate and a photon pumping operation. For three-dimensional clusters, which permit fault-tolerant universal computation, our protocol requires a two-dimensional grid of nearest-neighbor connected emitters.This paper is organized as follows. First, a brief overview of the graph state formalism is provided. Second, our new framework to produce arbitrary graph states using emitters, assuming entangling gates are available between emitters, is presented. Then, we discuss concrete realizations ...

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Section: Introductionmentioning

confidence: 99%

Generation of arbitrary all-photonic graph states from quantum emitters

2019

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“…To reconstruct the 3D image information clearly, the attacker needs to obtain the correct quantum key but also the correct image number, superimposition method, and image reconstruction algorithm. In mathematics, the normalized correlation coefficient (CC) can illustrate the image similarity, and is expressed as [38] CC = N n=1 (a n −ā n ) (e n −ē n ) N n=1 (a n −ā n ) 2 N n=1 (e n −ē n ) 2 (9) where a n andā n (or e n andē n ) are one pixel value and mean of original images (or reconstructed images), respectively. We calculate the CC value by only considering the correct rate of random codes in the quantum key, and the calculated result is shown in Figure 4A.…”

Section: Resultsmentioning

confidence: 99%

“…The protection of information and communication security is critical for the secret document transmission or important from data in order to improve existing methods in machine learning [7,8] ; blind quantum computation is a quantum computation model, which can release the client who does not have enough abundant knowledge and sophisticated technology to perform the universal quantum computation [9,10] ; quantum secure direct communication is to transmit the legitimate parties' secret message directly and securely in a quantum channel without creating a private key to encrypt and decrypt the messages. [11] Previous studies have demonstrated that the hybrid classicalquantum cryptographic technique can provide a very useful strategy to protect the information and communication security.…”

Section: Introductionmentioning

confidence: 99%

Compressed 3D Image Information and Communication Security

et al. 2018

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Ensuring information and communication security in military messages, government instructions, scientific experiments, as well as in personal data processing, is critical. In this study, a new hybrid classical–quantum cryptographic scheme to protect image information and communication security is developed by combining a quantum key distribution (QKD) and compressed sensing (CS). This method employs a QKD system to generate true random codes among the remote legitimate users and utilizes these random codes to encrypt and decrypt compressed 3D image information based on the CS algorithm. Therefore, this new technique can provide computational security in the image information transmission process by the encryption and decryption of CS algorithm, and the information and communication security can be evaluated in real time by monitoring the QKD system. Furthermore, this technique can directly transmit and reconstruct the compressed 3D image information based on the modified TwIST algorithm, and thus fewer random codes are required in QKD system, which can improve the information transmission bandwidth. Consequently, this technique not only provides a new application of a QKD system but also extends the CS‐based image reconstruction from 2D to 3D. This study may open a new opportunity in the field of information and security communication.

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“…Blindness may be required to protect user's privacy in future scenarios of delegated quantum computing [53]. In appendix D.2 we thus show how to make our protocol blind.…”

Section: Mesothetic Verification Protocolmentioning

confidence: 99%

Accrediting outputs of noisy intermediate-scale quantum computing devices

2019

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We present an accreditation protocol for the outputs of noisy intermediate-scale quantum devices. By testing entire circuits rather than individual gates, our accreditation protocol can provide an upperbound on the variation distance between noisy and noiseless probability distribution of the outputs of the target circuit of interest. Our accreditation protocol requires implementing quantum circuits no larger than the target circuit, therefore it is practical in the near term and scalable in the long term. Inspired by trap-based protocols for the verification of quantum computations, our accreditation protocol assumes that single-qubit gates have bounded probability of error. We allow for arbitrary spatial and temporal correlations in the noise affecting state preparation, measurements, single-qubit and two-qubit gates. We describe how to implement our protocol on real-world devices, and we also present a novel cryptographic protocol (which we call 'mesothetic' protocol) inspired by our accreditation protocol. measure [34-38] single qubits, however recently a protocol for a fully classical verifier was devised that relies on the widely believed intractability of a computational problem for quantum computers [39]. Other protocols for classical verifiers have also been devised, but they require interaction with multiple entangled and noncommunicating provers [40][41][42][43][44]. Cryptographic protocols show that with minimal assumptions, verification of the outputs of quantum computations of arbitrary size can be done efficiently, in principle.In practice, implementing cryptographic protocols in experiments remains challenging, especially in the near term. In experiments all the operations are noisy, as in figure 1(b), and the verifier does not possess noiseless quantum devices. Thus, the verifiability of protocols requiring noiseless devices for the verifier is not guaranteed. Moreover, the concept of scalability, which is of primary interest in cryptographic protocols, is not equivalent to that of practicality, which is essential for experiments. For instance, suppose that the target circuit contains a few hundred qubits and a few hundred gates. Cryptographic protocols require implementing this circuit on a large cluster state containing thousands of qubits and entangling gates [26][27][28][29][30][31]34] or on two spatially-separated devices sharing thousands of copies of Bell states [40,41]; or appending several teleportation gadgets to the target circuit (one for each T-gate in the circuit and six for each Hadamard gate) [33]; or building Feynman-Kitaev clock states, which require entangling the system with an auxiliary qubit per gate in the target circuit [35,39,43]. These protocols are scalable, as they require a number of additional qubits, gates and measurements growing linearly with the size of the target circuit, yet they remain impractical for NISQ devices.In this paper we present an accreditation protocol that provides an upper-bound on the variation distance between noisy and noiseless probability di...

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Private quantum computation: an introduction to blind quantum computing and related protocols

Cited by 186 publications

References 116 publications

Generation of arbitrary all-photonic graph states from quantum emitters

Generation of arbitrary all-photonic graph states from quantum emitters

Compressed 3D Image Information and Communication Security

Accrediting outputs of noisy intermediate-scale quantum computing devices

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