Contents | Start | End | Previous: KB0351: Why does Windows complain that files cannot be found, opened or written? | Next: KB0353: Can I embed fonts in an OpenDocument (ODT) file?
Sometimes you will be required to obfuscate your fonts in your Epub file such that they cannot easily be retrieved and used by someone reading your book.
You can use the configuration option Obfuscate fonts to do this. Set it to IDPF to use the IDPF's algorithm, as documented at www.idpf.org/epub/20/spec/FontManglingSpec.html.
This will mangle all the embedded fonts in your project using the first identifier specified in your metadata, so that unscrambling the fonts depends upon this identifier, making it harder (but not impossible) for people to retrieve the fonts. Jutoh also adds an encryption.xml file to the Epub book to indicate which files are encrypted.
Jutoh does the mangling on the fly when generating the Epub, so the embedded fonts in your project will remain intact and unobfuscated. You cannot currently obfuscate individual fonts: it's all or nothing.
Note that not all ereaders support this. It should work with Adobe Digital Editions for Epub 2 on Windows, and for Epub 2 and Epub 3 on Mac. It also works in Apple Books, Bluefire Reader and Calibre. However it doesn't work in AZARDI: the embedded fonts will simply be unrecognised and will revert to the default font. Kobo doesn't support them, and it probably won't work on Kindle either.
Treat this option with caution, and test your Epub files with as many ereader applications and devices as possible. If you distribute books via Amazon or other store, the ebook files will probably be encrypted, making obfuscation unnecessary.
Contents | Start | End | Previous: KB0351: Why does Windows complain that files cannot be found, opened or written? | Next: KB0353: Can I embed fonts in an OpenDocument (ODT) file?