Amazon’s Alexa examines the “acoustic fingerprint“ of your voice to recognize you…

The patent broadly describes two techniques. The first calls for transmitting a snippet of a commercial to Echo devices before it airs. Then the Echo can compare live commands to the acoustic fingerprint of the snippet to determine whether the commands are authentic. The second tactic describes how a commercial itself could transmit an inaudible acoustic signal to tell Alexa to ignore its wake word.