Full-Blind Delegating Private Quantum Computation

Abstract: The delegating private quantum computation (DQC) protocol with the universal quantum gate set $\left{ {X,Z,H,P,R,CNOT} \right}$ was firstly proposed by Broadbent \emph{et al.}, and then Tan \emph{et al.} tried to put forward an half-blind DQC protocol (HDQC) with another universal set $\left{ {H,P,CNOT,T} \right}$. However, the decryption circuit of \emph{Toffoli} gate (i.e., \emph{T}) is a little redundant, and Tan \emph{et al}.'s protocol exists the information leak. In addition, both of these two protocols just focus on the blindness of data (i.e., the client's input and output), but do not consider the blindness of computation (i.e., the delegated quantum operation). For solving these problems, we propose a full-blind DQC protocol (FDQC) with quantum gate set $\left{ {H,P,CNOT,T} \right}$ , where the desirable delegated quantum operation, one of $\left{ {H,P,CNOT,T} \right}$ , is replaced by a fixed sequence $\left { {H,P,T,CZ,CNOT} \right}$ to make the computation blind, and the decryption circuit of \emph{Toffoli} gate is also optimized. Analysis shows that our protocol can not only correctly perform any delegated quantum computation, but also holds the characteristics of data blindness and computation blindness.