A method and apparatus for communication via a computer network (102) including registering a plurality of users (206, 222, 224) with a trusted body (110, 210). The trusted body (110, 210) verifies the identity of each user (206, 222, 224) and generates a random identifier (216) for each user (206, 222, 224). A plurality of users (206, 222, 224) can enter into a dialogue with the other users by means of messages sent over the computer network (102) via the trusted body (110, 210). A user (206, 222, 224) remains anonymous through use of its random identifier (216) until such time as the user (206, 222, 224) reveals its true identity. Due to the registration of the users (206, 222, 224) with the trusted body (110, 210) a means of non-repudiation of the dialogue by the users (206, 222, 224) is provided.