Abstract: A method, system and program product for managing a size of a key management block (KMB) during content distribution is provided. Specifically, a first KMB corresponding to a first subtree of devices is received along with content as encrypted with a title key. If a size of the first KMB exceeds a predetermined threshold, a second subtree will be created. A second KMB corresponding to the second subtree of devices will then be generated. The second KMB contains an entry revoking the entire first subtree of devices and, as such, is smaller than the first KMD. Any compliant devices from the first subtree are migrated to the second subtree.

Abstract: A method, system and program product for managing a size of a key management block (KMB) during content distribution is provided. Specifically, a first KMB corresponding to a first subtree of devices is received along with content as encrypted with a title key. If a size of the first KMB exceeds a predetermined threshold, a second subtree will be created. A second KMB corresponding to the second subtree of devices will then be generated. The second KMB contains an entry revoking the entire first subtree of devices and, as such, is smaller than the first KMD. Any compliant devices from the first subtree are migrated to the second subtree.

Abstract: The present invention provides a method, system and program product for modifying content usage conditions during broadcast content distribution. Specifically, the present invention allows protected (e.g., encrypted, secured, etc.) content to be received along with content usage conditions, an encrypted combination of the content usage conditions and a title key (e.g., a MAC), and a key management block. Using the key management block, a key encrypting key can be determined for decrypting the combination. Once the combination is decrypted, the content usage conditions can be modified (e.g., edited, added to, etc.).

Abstract: A method and system for attaching a title key to encrypted content for synchronized transmission to, or storage by, a recipient is provided. Specifically, under the present invention, an elementary media stream is parceled into content units that each include a content packet and a header. The content packets are encrypted with one or more title keys. Once the content packets have been encrypted, the title keys are themselves encrypted with a key encrypting key. The encrypted title keys are then attached to the corresponding encrypted content packets for synchronized transmission to a recipient.

Abstract: An adaptive system for optimizing the bandwidth of a communication link in a communications session is disclosed. The decision as to when bandwidth in a communication session is to be released, or added, is based on the actual user activity rather than on an a priori determination which may not reflect the actual workload. Additionally, this decision is based on the actual costs associated with maintaining, releasing, and/or establishing a communication link or additional bandwidth. The costs include both direct costs and opportunity costs. The algorithm can also adapt its decision making process to its own performance, using feedback information to determine if it is minimizing the costs involved.

Abstract: A technique which efficiently approximates a continuous function employs volummetric linear interpolation and implements the interpolation process in an arithmetic apparatus which calculates a value v of the function according to: ##EQU1## where u.sub.i are scaling factors corresponding to specifically known points p.sub.i in a n-dimensional domain space of the function, v.sub.i are specifically known points in an m-dimensional range space of the function and k+1 is the number of specifically known points.

Abstract: The invention concerns the conversion of an input color to an output color using a multi-variable function having an input domain in a first three-dimensional color space and output range in a second m-dimensional color space. The conversion from input to output color subdivides the input domain into polyhedra defined by planar grids of points connected to form a plurality of triangles. The planar grids are projected into the remaining dimension of the function domain. When an input color value is presented, the multi-variable function is used to approximate the input value by computing an approximation of the multi-variable function, which provides a value in the output range. A tetrahedron containing the input color value is extracted from the function domain. The values of the multi-variable function at the tetrahedron vertices are obtained by interpolation. The tetrahedron is subdivided into subtetrahedra. The volumes of the subtetrahedra are calculated and multiplied by the function values.