Fault-Tolerant Operations for Universal Blind Quantum Computation

Blind quantum computation is an appealing use of quantum information technology because it can conceal both the client's data and the algorithm itself from the server. However, problems need to be solved in the practical use of blind quantum computation and fault-tolerance is a major challenge. Broadbent et al. proposed running error correction over blind quantum computation, and Morimae and Fujii proposed using fault-tolerant entangled qubits as the resource for blind quantum computation. Both approaches impose severe demands on the teleportation channel, the former requiring unrealistic data rates and the latter near-perfect fidelity. To extend the application range of blind quantum computation, we suggest that Alice send input qubits encoded with error correction code instead of single input qubits. Two fault-tolerant protocols are presented and we showed the trade-off of the computational overhead using the ten-bit quantum carry-lookahead adder as an example. Though these two fault-tolerant protocols require the client to have more quantum computing ability than using approaches from prior work, they provide better fault-tolerance when the client and the server are connected by realistic quantum repeater networks.