Inter-user privacy communication method and device

The invention provides a privacy communication method and device between users. A communication service system receives communication application information sent by a client of a first user, wherein the communication application information comprises zero-knowledge proof information used for verifying whether the first user holds an authorization key generated by a client of a second user. The authorization key is used for indicating the second user to authorize the first user to establish communication connection with the second user; zero-knowledge proof based on the zero-knowledge proof information is carried out to verify whether the first user holds the authorization key; and the verification result of the zero-knowledge proof is acquired; if the verification result indicates that the first user holds the authorization key, a communication connection is established between the client of the first user and the client of the second user, and thereby, the client of the first user and the client of the seco