Abstract: An audio signal-based method and system of authentication of a person in order to permit access to a secured resource. The system and method are configured to cause an audio sample to be produced by the computing device where a request for access is made. A secondary device on which a verification software application is installed can detect the playback of the audio sample. The secondary device can communicate with the authentication system to confirm detection of the audio sample. In response, the system can determine the user identity is verified, and can further be configured to automatically grant the person access to one or more services, features, or information for which he or she is authorized.