  How to solve the information leakage problem has become the research focus of
quantum dialogue. In this paper, in order to overcome the information leakage
problem in quantum dialogue, a novel approach for sharing the initial quantum
state privately between communicators, i.e., quantum encryption sharing, is
proposed by utilizing the idea of quantum encryption. The proposed protocol
uses EPR pairs as the private quantum key to encrypt and decrypt the traveling
photons, which can be repeatedly used after rotation. Due to quantum encryption
sharing, the public announcement on the state of the initial quantum state is
omitted, thus the information leakage problem is overcome. The
information-theoretical efficiency of the proposed protocol is nearly 100%,
much higher than previous information leakage resistant quantum dialogue
protocols. Moreover, the proposed protocol only needs single-photon
measurements and nearly uses single photons as quantum resource so that it is
convenient to implement in practice.
