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 Microsoft, the first of today's issuances describe ways of binding digital content to a portable storage device in a DRM system. Assigned to Sony, the second patent describes way of storing scrambled digital programs.
7,010,808, "Binding digital content to a portable storage device or the like in a digital rights management (DRM) system," assigned to Microsoft.
Digital content is rendered on a device by transferring the content to the device and obtaining a digital license corresponding to the content. A sub-license corresponding to and based on the obtained license is composed and transferred to the device, and the content is rendered on the device only in accordance with the terms of the sub-license. The content is encrypted and decryptable according to a content key, and the sub-license includes the content key encrypted and decryptable according to a secret. The sub-license also includes indexing information identifying the secret to the device. The indexing information in the sub-license is obtained to identify the secret, and the secret is acquired based at least in part on the indexing information. The secret is then applied to the encrypted content key to decrypt and obtain the content key, and the obtained content key is applied to the encrypted content to decrypt and obtain the content. To compose the sub-license and also to render the content, the secret is derived by obtaining a device identifier, acquiring a super-secret, and applying the obtained device identifier and super-secret to a function to derive the secret.
7,010,685, "Method and apparatus for storing scrambled digital programs by filtering product identifier," assigned to Sony.
In accordance with one embodiment, a method for storing a normal scrambled digital program is provided. The method includes receiving a scrambled program, and receiving a plurality of access requirements. Each access requirement can descramble the scrambled program. The method also includes selecting at least one of the access requirements, and storing the scrambled program and the selected requirement.