PROTECTING CONTENT FROM ILLICIT REPRODUCTION

摘要

A sufficient number of data items are selected (112) for inclusion in a data set so as to discourage a transmission of the entire set over a limited bandwidth communications path (130), such as the Internet. Each data item comprises one or more sections, which taken together constitute the complete data set. Each section of the data set is linked to another section of the data set, and each section's link is bound to the section via the use of one or more watermarks. Upon presentation of material for rendering, the presence of the entirety of the data set is verified (126) by ascertaining the presence of linked-to sections. For further security, the links between sections is formed by a random selection of each linked-to section. To verify that each linked-to section corresponds to the original section that was linked-to, each link contains an identifier of the linked-to section that can be used to determine that a retrieval of a linked-to section corresponds to the originally assigned linked-to section. If the identifier associated with the linked-to section does not properly match the presented linked-to section, a rendering of the data items of the data set is prevented. In a preferred embodiment, a closed linked list is formed, so that every section of the data set can be included in the verification process, if desired.