Every Thursday, the US Patent and Trademark Office publishes pending patent applications. Assigned to Intertrust, the first application describes ways of using cryptography for storage media electronic rights management in closed and connected appliances. Assigned to Widevine, the second application discloses ways of preventing entitlement management message (EMM) filter attacks.
20070185813, "Cryptographic methods, apparatus and systems for storage media electronic rights management in closed and connected appliances," assigned to Intertrust.
Abstract
A rights management arrangement for storage media such as optical digital video disks (DVDs, also called digital versatile disks) provides adequate copy protection in a limited, inexpensive mass-produceable, low-capability platform such as a dedicated home consumer disk player and also provides enhanced, more flexible security techniques and methods when the same media are used with platforms having higher security capabilities. A control object (or set) defines plural rights management rules for instance, price for performance or rules governing redistribution. Low capability platforms may enable only a subset of the control rules such as controls on copying or marking of played material. Higher capability platforms may enable all (or different subsets) of the rules. Cryptographically strong security is provided by encrypting at least some of the information carried by the media and enabling decryption based on the control set and/or other limitations. A secure "software container" can be used to protectively encapsulate (e.g., by cryptographic techniques) various digital property content (e.g., audio, video, game, etc.) and control object (i.e., set of rules) information. A standardized container format is provided for general use on/with various mediums and platforms. In addition, a special purpose container may be provided for DVD medium and appliances (e.g., recorders, players, etc.) that contains DVD program content (digital property) and DVD medium specific rules. The techniques, systems and methods disclosed herein are capable of achieving compatibility with other protection standards, such as for example, CGMA and Matsushita data protection standards adopted for DVDs. Cooperative rights management may also be provided, where plural networked rights management arrangements collectively control a rights management event on one or more of such arrangements.
20070180231, "Preventing entitlement management message (EMM) filter attacks," assigned to Widevine Technologies.
Abstract
A system, apparatus, and method are directed towards preventing entitlement/rights filter attacks in a conditional access to secure content over a network. An EMM that is configured to revoke access to selected content may be sent to a user, when a content provider, or the like, determines that access to the selected content is to be revoked for that user. A server may monitor for an acknowledgment of the revocation. If, after a predetermined time, a valid acknowledgement is not received by the server, the server may send another revocation EMM and again monitor for an acknowledgement response. If, after a predetermined number of retry attempts, a valid acknowledgement is not received, the server may send an alert message, investigate for possible network or device failures, change of encryption keys such as the CW, change a service key, or the like, for future content delivery to the user.
