Does anyone know about any ebook selling platforms that offer digital watermarking that uses steganography? i.e. to detect who has pirated your materials, via a secret message that dox'es the original purchaser.<p>I see no platform that will take your text (or PDF) and offer good watermarking. Or, for that matter, <i>any</i> watermarking besides a name and email on every page.<p>Name and email is easily defeated, because this is easily stripped.<p>A successful system would be a multi-pronged, steganographic watermark approach. The approach would, unfortunately, rely upon security by obscurity.<p>Whitespace approaches are good, but can be defeated by pdf2text followed by PDF creation. Nonetheless, they form a decent prong.<p>Additionally, there is a language-model (NLP) based approach based upon synonym substitution. Some common words can be replaced with synonyms without significantly altering the meaning of the text. So if word A has 8 replacements, I just added three bits to my secret message, the watermark. (I can't find the citation, sorry. If there is sufficient interest, I can dig it up. Or email me.)<p>Additionally, these approaches can be improved by adding error correction, in case there are minor modifications to the PDF.<p>As I said, these approaches are a weak form of security, but current approaches offer <i>no</i> security.<p>Exercise for the reader: If you can identify the pirate of your book, does this really matter? You can at best shame the pirate, but not undo their damage (widespread piracy), is my current understanding. Unless your technology is so good that, like Google with SEOs, people are sufficiently aware of your excellence that they are scared to even <i>dare</i> to try to beat you. Discuss.