Quote:
Originally Posted by ilovejedd
I expect it's super easy and cheap to do (probably just like adding serial numbers and something even Calibre can do easily). The watermark/hash isn't literally invisible. If you extract the epub (simple zip file) and view the underlying HTML with a simple text editor, you'll see the watermark/hash. It's just not visible when reading the ebooks via epub reader.
I believe comiXology does something similar for their DRM-free comics backups (granted, embedded in image files).
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It's not really cheap because the watermarking has to be individualized and recorded. That means that largely, it's done by humans. That's not remotely cheap, compared to regular DRM schema. That's what I was saying. Adding a simple bit of text/mark isn't expensive,
per se. The
expensive part is the individualization and recordation.
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