An authenticator in a second user device captures a media sample played on a first user device in proximity to the second user device. The media sample comprises at least one of an audio portion, a video portion or an image portion of a media stream received by the first user device from a remote media streaming source over a network. The authenticator sends at least a portion of the media sample from the second user device to an authentication server, the authentication server to compare the at least the portion of the media sample to a reference media stream received from the remote media streaming source to determine that the second user device is authenticated for viewing the media stream responsive to the portion of the media sample matching the reference media stream. The authenticator then receives an authentication decision from the authentication server at the second user device, the authentication decision indicating whether the second user device is authenticated.