Quote:
Originally Posted by jhowell
Font obfuscation encrypts embedded font files as a weak from of copy protection. The obfuscation algorithm uses the identifier of the book in the OPF file as the encryption key. The presence of an excryption.xml file along with the garbled contents of the fonts in your book shows that font obfuscation was applied to the book at some point. Changing the book identifier after the fact has rendered the embedded fonts unusable.
You can read more detail in the blog post Font obfuscation in EPUBs and why you shouldn't change the dc:identifier after exporting from InDesign.
I am not familiar with how Sigil handles font obfuscation. Someone else will have to comment on that. |
I read your blog post and it was very helpful. However, restoring the identifier did not solve the problem, nor did re-exporting and replacing the info in the content.opf and encryption.xml files.
There was a lot of little things I had to do in HTML and CSS, once I exported from InDesign, that I would have to redo in the main XHTML and CSS files if I started from scratch again. Naturally, I prefer to avoid that, especially when it's on ONLY the iPad Pro that the book does not function. I would think that the obfuscation and encryption key issues would have rendered the book as blank on all devices if that was what was causing this?
My best option may be to re-export WITHOUT fonts embedded and edit the CSS files accordingly, then replace and edit the stylesheet references. I know how to do this; I'm just frustrated that there's not a clear solution to the problem.
Thanks for your help. No more tinkering with the identifier.