Unreferenced object in page rendered electronic file

摘要

An electronic file includes a page rendered version of a document and at least one unreferenced object embedded therein. The unreferenced object serves as a virtual watermark with respect to the electronic document. The electronic file may be an electronic file in Portable Document Format. The at least one unreferenced object may be an XObject. The electronic file of also may include at least one fixed location referenced object and at least one variable location object. The unreferenced object may be a placeholder object configured to be populated with a specific value in a subsequent production process while the electronic file remains encrypted. The unreferenced object may include information that identifies a location for at least one other object.