Patent ID: 8407473

Claim:
An electronic device comprising: a processor; a storage unit configured to store computer program instructions which when executed by the processor cause the processor to: generate first authentication data; output a first response request, which is transmitted to a second electronic device, said first response request includes data generated based on said first authentication data; generate an expected value based on the first authentication data; receive a first response message based on said first response request command, said first response message transmitted from said second electronic device and including second authentication data based on said first authentication data, wherein the expected value is generated prior to receiving the first response message; output a second response request command, which is transmitted to the second electronic device, after receiving the first response message; receive a second response message based on the second response request command, said second response message transmitted from said second electronic device and including third authentication data generated at the second electronic device based on said first authentication data; measure a response time of the second response message received from said second electronic device; generate an authentication result for said second electronic device based on said expected value and said third authentication data included in said second response message; and judge if said second electronic device is authorized to use content data based on the authentication result and the response time.