Patent ID: 7565700

Claim:
A method for managing time based digital rights control in a device that doesn't have a secure clock, comprising: defining a universal time interval (UTI) for a plurality of devices; establishing a device time interval (DTI) corresponding to a first device of the plurality of devices, wherein the DTI is a repeatable time based measurement that is convertible into UTI and based upon operational characteristics of the first device; associating a first availability time interval (ATI) with content subject to a rights control policy; receiving the content and associated first ATI at the first device; converting the first ATI into DTI units; storing the content in conjunction with the DTI units; modifying the DTI units based upon an a usage based control (UBC) policy; generating a unique identifier corresponding to the content; comparing the unique identifier to a previously generated and stored unique identifier; making a determination concerning access to the content based upon the modified DTI units and whether or not the unique identifier matches the previously generated and stored unique identifier; deleting the content if the determination concerning access is that the first device does not have authorization to access the content; receiving a request at the first device to transmit the content to a second device; converting the DTI into a second ATI; and transmitting the content in conjunction with the second ATI to the second device.