Conditional access using embedded watermarks

摘要

Methods, devices and computer program products facilitate conditional access to a content embedded with watermarks. For such a content, when copy control rules associated with an embedded watermark message prohibits unconditional access to the content, it is determined whether or not an exception to the copy control rules exists, and if an exception to the copy control rules exists, the content is conditionally accessed. Additional watermark messages can be extracted while the content is being conditionally accessed, and based on the additionally extracted watermark messages, it is verified that conditional access to the content has been fulfilled.

主权项

1. A method, comprising:
extracting an embedded first watermark message from a content by a watermark extractor that is implemented at least partially in hardware, wherein the content includes the first embedded watermark message, a second embedded watermark message and additional watermark messages embedded therein, and wherein the embedded first watermark message is a copy control watermark and copy control rules associated with the extracted first watermark message prohibits unconditional access to the content; extracting the embedded second watermark message from the content, wherein the second watermark message includes a different value than the first watermark message; based on the extracted second watermark message, determining whether or not an exception to the copy control rules exists, and upon a determination that an exception to the copy control rules exists; enabling a conditional access to the content; extracting the additional watermark messages from the content while the content is being conditionally accessed; and based on the additionally extracted watermark messages, verifying that the conditional access to the content has been fulfilled for at least the sections of the content that include the additionally extracted watermark messages, wherein verifying that the conditional access to the content has been fulfilled includes determining whether all or only sections of the content that are subject to the conditional access have been accessed, and triggering an additional action upon a determination that only sections of the content that are subject to the conditional access have been accessed, wherein the copy control rules associated with the first watermark message are applicable to the content as initially released to public, and the second watermark message enables the determination as to whether or not a new exception to the copy control rules exists based on elapsed time from the initial public release date of the content.