Quote:
Originally Posted by sgirsberger
I did change the book identifier to the eISBN for this book, but I don't understand what you mean by the font obfuscation being broken. I didn't change anything to do with the obfuscation when exporting, unless removing the arbitrarily assigned book identifier resulted in that? I usually keep just the eISBN as the book identifier.
Would appreciate further explanation. When I opened this in Sigil 0.9.6, I check to see if any font obfuscation was present, and none was checked. If I should check an option, should it be Adobe's method or IDPF's method? I know that often, Adobe's is applied when exporting with fonts embedded from InDesign.
|
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.