Abstract: A document accessible over a network can be registered. A registered document, and the content contained therein, cannot be transmitted undetected over and off of the network. In one embodiment, the invention includes maintaining a plurality of stored signatures, each signature being associated with one of a plurality of registered documents, intercepting an object being transmitted over a network, calculating a set of signatures associated with the intercepted object, and comparing the set of signatures with the plurality of stored signatures. In one embodiment, the invention can further include detecting registered content from the registered document being contained in the intercepted object, if the comparison results in a match of at least one of the signatures in the set of signatures with one or more of the plurality of stored signatures.