Patent ID: 7398392

Claim:
A method for distributing digital content from a sending device to an authorized receiving device which is located at a predetermined location and whose authentication data has been compromised by an unauthorized receiving device, the method comprising the steps of: determining a predetermined distance from said sending device to said authorized receiving device, where said authorized receiving device is located at a predetermined location that is known to said sending device; receiving a request for digital content from a device purporting to be said authorized receiving device; sending, in response to said request for digital content, a request for acknowledgement to said purported receiving device; receiving an acknowledgement, including device authentication data, from said unauthorized receiving device that corresponds to valid device authentication data from said authorized receiving device; determining, in response to receiving said acknowledgement from said purported receiving device, an actual round-trip response time for said request for said acknowledgement and the associated acknowledgement; and using said actual round-trip response time to determine if said purported receiving device is located a distance from said sending device corresponding to said predetermined distance from said sending device to said authorized receiving device.