Quote:
Originally Posted by kacir
There are instances of "Social DRM" where Credit Card info is visibly embedded in a purchased book. Or at least were in the past.
As far as I am aware, no big sellers of DRMed epubs are embedding secret identifying info into books. Yet.
We will never be able to tell for sure. Unless you compare files purchased by different people from the same publisher. After removing DRM, of course. Because DRM protected files have to be different for different customers.
What if they started yesterday? It doesn't have to be something obvious or visible. It might be stenographically hidden in a cover image, it might be a difference of a few spaces or newlines or use of lowercase/uppercase letters inside the xhtml tags in epub markup. You could even encode info inside a book plain-text by using a few extra spaces before newlines, or a combination of different versions of typographical quotes or use of ligatures, so it might even survive a format conversion to a plain text.
They do not even need to start to embed the info. Just change a few pixels in a cover or a few characters in an html tag to make would-be pirates paranoid. That is what I would consider doing if I was a publisher <maniacal laugh> ;-)
Mind you, I consider the above scenario unlikely.
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The Social DRM I've encountered in the last couple of years (buying printable PDFs with a family/single classroom licence) uses a 'licenced by name and email address' watermark which seemed reasonable.