A method and a system for identity authentication are presented. In one example embodiment, audio data (e.g. a sound wave) may be received from a user. The audio data may be used to establish an identity of a first entity to the user. The audio data may be stored at a storage location; and be presented to the user to establish the identity of the first entity when the first entity participates in an electronic communication with the user. In another example embodiment, a server (e.g., a web client or client application server) may present a plurality of audio data instances to a user; receive the user selection of selected audio data from the plurality of audio data instances; responsive to the user selection, the server may communicate, via a network, the selected audio data to another server. The selected audio data may be used as an identity authentication.