View Full Version : font encryption, mangling, legal


mzmm
03-20-2013, 07:53 AM
hi all,

i have question here about the legalities of embedding proprietary fonts into ebooks, either mobi or epub (but i like epub better so i'm starting the thread here).

PREAMBLE: i have no motivation or desire to embed proprietary fonts in ebooks, but this is a question i encounter periodically and i've never really come across a satisfactory answer.

i'm aware that Apple supports embedded fonts that have been mangled, but not encrypted. the asset guide has a single line that includes a link to the IDPFs font mangling section, but no information on how what the legal ramifications are.

Adobe Indd (since CS6) auto mangles and encrypts fonts, so that seems like the fonts would remain copy-protected, but again, i haven't been able to find out if this actually does permit one to distribute the ebook legally.

so, the question is this:

if a proprietary font is either mangled or encrypted, or both, is that sufficient to permit one to distribute the ebook?

and to follow up, are there e-readers that are incapable of decrypting or de-mangling(?) that would basically make including them in this way useless anyway?

or are there particularities in the licence of the font itself that would specify the level of encryption legally required to embed the font in an ebook?

thanks in advance!

user_none
03-20-2013, 08:35 AM
if a proprietary font is either mangled or encrypted, or both, is that sufficient to permit one to distribute the ebook?
No. Even mangled you're still distributing the font.


and to follow up, are there e-readers that are incapable of decrypting or de-mangling(?) that would basically make including them in this way useless anyway?
Yes. But the same can be said for CSS. The major readers on the market support embedded fonts and font mangling. Worry about where you want to sell books and what those stores support not all possibile devices out there.


or are there particularities in the licence of the font itself that would specify the level of encryption legally required to embed the font in an ebook?
Yes. License is the key word here. You don't own the font and can only do what the license allows. For example some font licenses have clauses that say you can distribute it all you want but you have to pay $1 for every copy.

mzmm
03-20-2013, 12:51 PM
@user_none - thanks for the concise replies! onto researching the wonderful world of font licences.

AlPe
03-20-2013, 03:35 PM
My two three cents.

A) Forget about (commercial) embedded font. There are plenty of freely embeddable fonts out there (e.g., under Open Font License or LaTeX Project Public License).

B) Consider NOT to use embedded fonts altogether: many Reading Systems do not offer the user with the option of NOT using the Publisher's default font, and the user gets annoyed.

C) Personally, I use embedded (open) fonts only for titles or when certain special glyphs are needed. (And, BTW, my glyphIgo (http://code.google.com/p/glyphigo/) tool might be useful to minimize them.)

dgatwood
03-21-2013, 01:43 AM
No. Even mangled you're still distributing the font.


Well, yes and no. Most font licenses do include the right to embed a subset of the font so long as it is not trivially extractable. Whether the mangling/encryption schemes currently available really qualify or not is dubious, IMO, but then again, all DRM is dubious by nature, so I would say that it is not really any more dubious than embedding a font subset in a PDF.

However, as you said, whether you can do this or not depends on your license.

Whether readers can unmangle the fonts or not likely depends on the reader and on whether you use Adobe's proprietary standard (http://www.mobileread.mobi/forums/showthread.php?t=143240) or the official one (http://idpf.org/epub/20/spec/FontManglingSpec.html), but yes, there probably are readers that will barf.

mzmm
03-21-2013, 06:47 AM
My two three cents.
A) Forget about (commercial) embedded font. There are plenty of freely embeddable fonts out there (e.g., under Open Font License or LaTeX Project Public License).

i totally agree with you on this one. i would only ever embed fonts with open licences when working on my own projects, but i've spoken to a number of designers who've laid something out a particular way and want it rendered 1:1 (which i try to explain isn't going to happen anyway. another topic).

B) Consider NOT to use embedded fonts altogether: many Reading Systems do not offer the user with the option of NOT using the Publisher's default font, and the user gets annoyed.

i thought so too, but am starting to think that a lot of popular devices do actually offer embedded font support, although default to device-fonts. i was actually trying to find a comprehensive (or close to comprehensive) list of devices and the level of embedded font support, like not just if the reader supports the @font-face declaration, but actually makes it available for readers to choose them.

C) Personally, I use embedded (open) fonts only for titles or when certain special glyphs are needed. (And, BTW, my glyphIgo (http://code.google.com/p/glyphigo/) tool might be useful to minimize them.)

yeah i noticed your util on the forum a while ago - thanks by the way - but haven't played around with it much. i've used font-squirrel to subset a font for one or 2 special characters in the past, but might try yours out in the future to subset title fonts.

mzmm
03-21-2013, 06:56 AM
Most font licenses do include the right to embed a subset of the font so long as it is not trivially extractable.

thanks for the feedback and the links! the phrase "not trivially extractable" sounds really open to interpretation. "open to interpretation" and "legal" in the same sentence i try to stay away from.

DaleDe
03-21-2013, 01:55 PM
thanks for the feedback and the links! the phrase "not trivially extractable" sounds really open to interpretation. "open to interpretation" and "legal" in the same sentence i try to stay away from.

Pretty much everyone uses the same obfuscation method for fonts and it is the one supported by Adobe for all devices using the Mobile ADE API. It is generally what is meant by "not trivially extractable"

Dale

dgatwood
03-22-2013, 02:27 AM
Pretty much everyone uses the same obfuscation method for fonts and it is the one supported by Adobe for all devices using the Mobile ADE API. It is generally what is meant by "not trivially extractable"


Most of those terms of use were written before EPUB existed, and mostly referred to embedding in a PDF file, which is a lot harder to extract fonts from than an EPUB. This is the sort of situation where if there's any question about it, I'd want to get clarification from the foundry's legal department before including the font.

As an aside, I've recently been playing (not in an EPUB) with embedding fonts as a data URL programmatically inlined into a CSS file, which is, in turn, programmatically inlined as a data URL in a link element (along with images, etc.). Now that is obfuscation on the same order as what PDF does. :D