Does anyone know anything about automatic document watermarking or fingerprinting, as in, do certain
online magazine publishers do it?
For those unaware, systems exist to automatically add encoded and hidden information (for instance the username of downloader
) to documents as they are downloaded from a server. Obviously useful for purposes such as copyright enforcement!
Some time ago there was a rumour that this was happening, and at the time I managed to obtain a document from two different sources, and there was no difference between them. That would indicate that such watermarking was not happening at the time. It was quite some time ago though, and things could well have changed.
