Secure Two-Party Computation Based on Blind Quantum Computation

Two-party quantum computation (2PQC) allows two participants Alice and Bob to securely compute a given unitary function on their quantum inputs without leaking privacy. Existing 2PQC protocols require participants to have strong quantum capability, such as preparing qubits and performing measurements. Recently, Kashefi et al. proposed a 2PQC protocol named QYao protocol, where Alice only has to prepare qubits and perform Pauli operations, but Bob needs to have a powerful quantum computer. In this paper, we simplify the QYao protocol and reduce Bob’s quantum capability by applying blind quantum computing (BQC) in 2PQC. Two improved 2PQC protocols are proposed. The first protocol allows Bob to generate his encrypted input by making measurements and thus removes encryption at the input stage. The second protocol improves the verification capability of Bob based on the method of stabilizer testing and further reduces Bob’s ability to make measurements only. Besides, Alice can be more flexible since it is enough for her to produce an appropriate graph state instead of a fixed dotted triple-graph resource state DT(G). After the computation, two parties’ inputs also can be kept secret in both presented protocols.