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Due to the entanglement effect of the register and ancilla, arbitrary quantum opera-
tions on qubits of the register can be realized by performing suitable measurements
on the ancilla. ADQC has excellent advantages in some physical systems where
register qubits with long decoherence time are difficult to operate, while relatively
short-lived ancilla qubits are easier to control and can be prepared and measured
quickly, such as neutral atoms in optical lattices [14], cavity QED superconducting
qubits [15], and aluminum ions in optics [16,17]. Besides, ADQC can simulate any
positive operator valued measurement (POVM) on register qubits by accessing a
fully controlled ancilla which is attached to the register sequentially. Therefore, it
is also useful for experimental systems where their measurements would destroy
physical qubits, such as photonic systems.
Although quantum computation has been extensively studied, the physical real-
ization of it is still very challenging. Even if quantum computers become available,
they are likely to be owned by only a handful of centers around the world much like
today’s supercomputer rental system. Clients who want to utilize these quantum
resources can only delegate their computational tasks to the organizations that own
quantum computers. The burdens of clients are greatly reduced in such a delegated
quantum computing model, but their privacy is seriously threatened. Fortunately,
some quantum cryptographic techniques, such as quantum key distribution [18,19],
quantum identity authentication [20,21], and quantum secret sharing [22], can be
utilized to protect the privacy of clients.
Blind quantum computation (BQC) as a combination of quantum computation
and quantum cryptography is a kind of delegated quantum computing that can
protect private data of clients. It allows a client who only has some simple quantum
devices to delegate quantum computing tasks to a powerful quantum server, while
keeping the data of the client including input, output, and algorithm hidden from the
server. The first BQC protocol was proposed by Childs based on the circuit model
[23], where the client Alice must possess quantum memory, prepare |0i, and have the
ability to perform SW AP gates. Broadbent, Fitzsimons, and Kashefi proposed the
first universal BQC protocol (known as the BFK protocol) [24], in which the client
only needs to prepare single-qubit states and does not require quantum memory
and the ability to perform complex quantum gates. Then Morimae et al. proposed
another BQC model [8] in which the client only makes measurements, as in some
experimental settings such as quantum optical systems, the measurement of a qubit
is much easier than generating a single-qubit state. Since then, a series of BQC
protocols were proposed based on these two protocols [25–35] and a few proof-of-
principle experiments were demonstrated in photonic systems [36,37]. Recently, Li
et al. proposed a new model of BQC where a client only needs to perform several
single-qubit gates [38] and it provides a new research path for BQC.
An ancilla-driven blind quantum computing (ADBQC) protocol was proposed by
applying the BQC technology to the ADQC model [39], which realized the ADQC
in the way of delegated quantum computing for the first time. After that, another
ADQC protocol without performing measurements was proposed to further enrich
the field of ADQC [40]. In ADBQC, it is implemented in a very monolithic way,
and clients should generate various single qubits. In fact, it is unrealistic that all
users have the same quantum ablitity. As mentioned above, BQC mainly deals with