Circuit-model blind quantum computation with key decoupling

In the noisy intermediate-scale quantum (NISQ) era, quantum computing resources are increasingly provided through cloud platforms, enabling users to perform quantum computations without owning expensive hardware. However, delegating computations to remote servers raises a key challenge: ensuring the privacy of the client’s input, algorithm, and output. To address this issue, we propose a circuit-model blind quantum computation (CMBQC) protocol that conceals the target quantum computation while decoupling the encryption and decryption keys. This key-decoupled structure avoids gate-by-gate propagation of decryption information on the client side. We establish blindness of the target operation within its Pauli equivalence class and prove the verifiability of the protocol, where verification is achieved by estimating expectation values of randomly chosen Pauli observables, thereby substantially reducing the verification overhead. We further demonstrate a single-qubit implementation of the CMBQC protocol on an International Business Machines Corporation (IBM) superconducting quantum system. The simple structure and low verification cost of the CMBQC protocol make it a promising framework for secure delegated quantum computation, with potential applications in quantum cloud computing.