The US Patent Office issues new patents on Tuesdays. Issued patents and published applications may be early indicators of the kinds of issues being addressed by inventors and/or the companies for whom they work. Assigned to ContentGuard, the first of today's patents discloses a system for controlling the distribution and use of digital works. Assigned to Philips, the second patent addresses the use of a time-dependent watermark for the purpose of copy protection.
6,934,693, "System for controlling the distribution and use of digital works," assigned to ContentGuard.
A system for controlling the distribution and use of digital works using digital tickets. In the present invention, a "digital ticket" is used to entitle the ticket holder to exercise some usage right with respect to a digital work. Usage rights are used to define how a digital work may be used or distributed. Each usage right may specify a digital ticket which must be present before the right may be exercised. Digital works are stored in repositories which enforce a digital works usage rights. Each repository has a "generic ticket agent" which punches tickets. In some instances only the generic ticket agent is necessary. In other instances, punching by a "special ticket agent" residing on another repository maybe needed.
6,934,851, "Method and apparatus for use of a time-dependent watermark for the purpose of copy protection," assigned to Philips.
A copy protection system for protecting content wherein a ticket and a watermark are created, utilizing a first time reference (TD) and a one-way function, to indicate the copy protection status of the content. A source device produces the ticket and watermark using a first time reference and a hashing function. The source device provides a data stream containing the content, the ticket, the watermark, and the first time reference (TD) to the receiver device. The receiver device determines if the first time reference (TD) is contained within a time window determined by a second time reference. When, the first time reference (TD) is contained within the time window, the receiver compares the ticket to the watermark using the first time reference (TD) and the one-way function, and based on the comparison, produces a signal indicating the copy protection status of the content.