System for permitting off-line playback of digital content, and for managing content rights
Patent 6915425 Issued on July 5, 2005. Estimated Expiration Date: 
December 13, 2020. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
December 13, 2020. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesCreation and distribution of cryptographic envelope Patent #: 5673316 InventorsApplicationNo. 09739076 filed on 12/13/2000US Classes:713/165, File protection380/201, Copy protection or prevention705/51Usage protection of distributed data filesExaminersPrimary: Smithers, MatthewAttorney, Agent or FirmInternational ClassesH04L009/32H04N007/16 AbstractA system for permitting offline content playback and for managing the rights to one or more digital content files within a computer network. The system manages these rights by encrypting the content files to prevent unauthorized access to the files. Encryption is accomplished by using one or more keys which are associated with one or more segments of the content file. These keys enable an authorized user to decrypt and playback the content files at a subsequent time. When the keys are received, a license which specifies the rights of the user regarding the content files, is obtained by the end user system, and verified locally to permit the content playback. | |
