Patent ID: 8239961

Claim:
A method of monitoring time, comprising: calculating, using a central processing unit (CPU), a first calculated time value corresponding to a point in time when content is used by a client on a first occasion, wherein the first calculated time value is a function of a first trusted time value received by the client from a trusted authority external to the client during a first communication session; calculating a first time offset value corresponding to a difference between a second trusted time value and a second calculated time value, wherein the second trusted time value is received by the client from the trusted authority during a second communication session, and wherein the second calculated time value corresponds to a point in time when the second trusted time value is received by the client, and wherein the second calculated time value is a function of the first trusted time value; and calculating an elapsed time value corresponding to a difference between a third calculated time value and a revised first calculated time value, wherein the third calculated time value corresponds to a point in time when the client attempts use of the content for a second occasion, and wherein the third calculated time value is a function of the second trusted time value, and wherein the revised first calculated time value corresponds to a combination of the first calculated time value and the first time offset value.