Suppose that I have a tex-based PDF manuscript with math content. I am wondering if it is possible to "sabotage" attempts to convert that PDF to EPUB.

Specifically, I am wondering if all math content in the PDF can be marked up someway "under the hood" of the PDF so that if an attempt is made to convert it to EPUB, the math will come out saying "Hello There!" or some other message of my choosing.

I'm fine if all my math source has to change to something like \begin{math}...\end{math}. I'm imagining something like that and inserting something into the PDF structure with each such environment.

I am suffering from a very poor understanding of PDF and how EPUB conversion works. I appreciate any attempt to educate me on why what I am considering is not possible. And of course I appreciate even more any advice on how to make it actually happen :)

This question is motivated by a math textbook whose PDF is freely available and openly licensed. The problem is that rogue actors on the internet automate creating EPUB from the PDF. We don't care that they try to sell the EPUB, but we do care that the math is garbage. We would like to redirect would-be readers to the real source PDF.

  • 2
    My answer to "How can I protect a pdf" is usually you can't since like a book anyone who can read it can photograph it or with a computer its easier to screen grab or convert the data stream, In this case you could consider stenography (in) or watermarks (on) images of your math, it would not stop the jack sparrows but it might slow them down and if poorly done would show up as copied. In all cases the time taken to protect is usually not worth it. If my ancestor who invented the first stone tablet had copyrighted it I'd be a gazillionaire by now. – KJO Oct 24 '18 at 1:24
  • @KJO I get all that. Is it clear that I'm not trying to protect the copyright? I'm concerned about the broken math. It's a low-level math textbook, and the typical reader will not necessarily recognize that the symbols in front of them are garbage. – alex.jordan Oct 24 '18 at 1:28
  • On this forum your asked to give a mwe :-) in this case an image or two to compare the affect and thus effect might help P.S spellchecker changed Steganography to stenography but I guess you got the drift – KJO Oct 24 '18 at 1:37
  • Your tex is converted to frames & streams of images/text. The text can be chopped to make it harder to copy a stream but most hackers can easily script around that, hence the suggestion to concentrate on images. The nearest method to ''pop up'' an ''I'm watching you'' warning is to frequently embed hidden text and there are several questions such as ''How can I hide comments behind an image / hide a comments box'' That's possibly all you could do, but it's unlikely to be transfered if changes are made, nor would it stop a con'sverter, but hopefully I could be wrong. – KJO Oct 24 '18 at 2:07
  • I have to wonder whether this might be done with a JavaScript implementation and forms. In essence, put the math or some other important text in a locked text field with a dark gray background (so the text is essentially hidden). Have a "Clear Math/Text" button that resets the background on the form field from dark gray to white. AFAIK, this trick would translate to the EPUB as a bunch of dark gray boxes. – Jeffrey J Weimer Oct 24 '18 at 2:39

I prefer the devils advocate view. make it so easy to copy they can't avoid it enter image description here

  • (a) That's my taco question from math.se. (b) I am a WeBWorK developer. (c) I've asked on latex.se about making the math latex automatically visible or accessible to readers. Coincidences? – alex.jordan Oct 24 '18 at 14:11
  • Are you manually adding that latex source alongside the math, or do you only type it once, and it is somehow automated to come out in both math and source forms? – alex.jordan Oct 24 '18 at 14:13
  • Nothings coincidental some say 1^2=\sqrt 1 & we are just = the result of chaos. For illustration its done by cut and paste. The idea is that if you wish readers to get the true source rather than OCR corruption of TeXmath the best way is to include the plain TeX alongside just copy and past text into a box ? Thus to make it easy for readers to check the content. Frequent links to source locations can be interspersed at relevant locations to avoid a simple positional mask of header or footing, with lucky 1 or 2 would get past robot scripts especially if combined into edge of any core images. – KJO Oct 24 '18 at 16:44

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