Patent attributes
A system and method for controlling access to digital content based on proximity and location of a user device. A user device connects to a local network and an audio transmission including a perpetually rolling key is transmitted within a geo-fence in the local area. The user device hears the audio transmission and uses the key to authenticate to a content server over the network. Once authenticated, the user device may then stream content from the content server. In order to terminate access to the content when the user device leaves the geo-fence, the content server may require the key to be retransmitted from the user device at regular intervals to re-authenticate the user device. Other factors such as radio fingerprints from the user device may also be used instead of or in addition to the audio to verify the user device's presence within the geo-fence.