Verifiable single client-server Blind Quantum Computation based on measurement
Xiaoqian Zhang, Jian Weng, Weiqi Luo, Xiaoqing Tan · arXiv (Cornell University) · 2018
The characteristics of BQC is that it enables a client with less quantum abilities to delegate her quantum computation to a server with strong quantum computablities while keeping the client's privacy. In this article, we study single client-server BQC based on measurement which is verifiable. In detail, the verifiability is that the client Alice can obtain the correct measurement results if the server Bob is honest, while Bob does not get nothing of Alice's secret information if he is malicious. We construct a latticed state, composed of six-qubit cluster states and eight-qubit entangled states, to realize Alice's quantum computing. In this proposed protocol, the cilent Alice prepares and sends initial single-qubit states to Bob, where the initial states include useful qubits and trap qubits. And then Bob performs controlled-Z gate to produce the entanglement and returns them to Alice. Alice will send trap qubits and useful qubits to Bob randomly and Bob returns all measurement results to her. Alice makes a comparison for trap qubits between true results and Bob's results to check the honesty of Bob. In a word, the trap qubtis have two purposes: 1) confusing Bob to keep the blindness; 2)verifying the honesty of Bob and correctness of Bob's quantum computing. There has an important feature that Alice does not need to encrypt the computing angles by $r\pi$ (r$\in\{0,1\}$), meanwhile the blindness and correctness can also be ensured. That is, Alice's computing results don't need to flipped since Bob is not impossible know anything about the quantum computation. Our work gives a better understanding for verifiable BQC based on measurement.