Digital rights management using trusted time
OwnerMarc E. Strohwig, Yoji Kawamoto +5inventors
InventorsMarc E. Strohwig, Yoji Kawamoto, Motohiko Nagano, Pierre Chavanne, Norifumi Goto, Oscar H. Steele, III, Eric John Swenson
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Abstract
A method for monitoring time so that the use of protected content can be controlled includes receiving a trusted time value from a trusted authority external to a client device. When the client is no longer in communication with the trusted authority, the previously-received trusted time value is updated by use of the client's operating system counter so that a calculated trusted time value is derived for content license evaluation purposes.
Claims7
A method of controlling the use of content, comprising:
- securely storing a first time value corresponding to a point in time when a first client was most recently in communication with a trusted authority;
- securely storing a second time value corresponding to a point in time when at least a subsystem of an application was most recently initialized, the application being adapted for using the content;
- transmitting a flag from the first client to a second client if the first time value is greater than the second time value;
- and
- permitting use of the content by the second client if the second client has received the flag.
A method of controlling the use of content, comprising:
- transmitting a first time value and a second time value from a first client to a second client,
- wherein the first time value corresponds to a point in time when the first client was most recently in communication with a trusted authority, and
- wherein the second time value corresponds to a point in time when at least a subsystem of an application was most recently initialized, the application being adapted for using the content;
- and
- permitting use of the content by the second client if the first time value is greater than the second time value.
An article of manufacture for controlling the use of content and for use by a first client and a second client, wherein each of the first and second clients has a processing unit, and wherein the first client is adapted for communication with a trusted authority external to the first client, the article of manufacture comprising:
- a first computer usable media and a second computer usable media,
- wherein the first computer usable media includes a first computer program embedded therein, the first computer program having a subsystem and being adapted to cause the first client to perform:
- securely storing a first time value corresponding to a point in time when the first client was most recently in communication with the trusted authority;
- securely storing a second time value corresponding to a point in time when at least the subsystem of the first computer program was most recently initialized;
- and
- transmitting a flag from the first client to the second client if the first time value is greater than the second time value;
- and
- wherein the second computer usable media includes a second computer program embedded therein, the second computer program being adapted to cause the second client to use the content if the second client has received the flag.
A system for controlling the use of content, the system being adapted for communication with a trusted authority, the system comprising:
- a first client having a first processing unit capable of executing software routines, and having a first programming logic executed by the first processing unit;
- and
- a second client having a second processing unit capable of executing software routines, and having a second programming logic executed by the second processing unit,
- wherein the first programming logic comprises:
- means for securely storing a first time value corresponding to a point in time when the first client was most recently in communication with the trusted authority;
- means for securely storing a second time value corresponding to a point in time when at least a portion of the first programming logic was most recently initialized;
- and
- means for transmitting a flag from the first client to the second client if the first time value is greater than the second time value;
- and
- wherein the second programming logic comprises:
- means for using the content if the second client has received the flag.
Dependencies are inferred from the claim text.