Preventing Sigil embedded font files from user access

[bobcdy]

Does anyone know if whether in Sigil there is any way to prevent epub embedded font files from being accessed by anyone except the epub author?

[JSWolf]

Originally Posted by bobcdy

Does anyone know if whether in Sigil there is any way to prevent epub embedded font files from being accessed by anyone except the epub author?

No way at all.

[eschwartz]

Well, there are ways to obfuscate font files so they aren't useful for redistribution -- but that isn't the same as rendering the actual file on disk inaccessible.

[Toxaris]

Is not so much a Sigil issue as more a format issue.

[Doitsu]

Originally Posted by bobcdy

Does anyone know if whether in Sigil there is any way to prevent epub embedded font files from being accessed by anyone except the epub author?

You can obfuscate the fonts, which will make them useless to the average user:

1. Select all fonts in the Font folder.
2. Right-click them and select Font obfuscation > Use Adobe's method.
3. Save the epub file.

Note that font obfuscation will not trigger the change asterisk in the Sigil menu bar. However, you can verify that it worked by unzipping the ePub file and double-clicking an obfuscated font. Windows will then tell you that it's not a valid font file.

[user_none]

Originally Posted by Doitsu

Note that font obfuscation will not trigger the change asterisk in the Sigil menu bar.

This will be fixed in the next release. Any change to the books content should result in a the user being notified that the book has changed and needs to be saved.

[Hitch]

Originally Posted by bobcdy

Does anyone know if whether in Sigil there is any way to prevent epub embedded font files from being accessed by anyone except the epub author?

bobcdy:

If the gist here is to use a font in an eBook, and preclude someone down the line from being able to install/use the font without licensing same, simply use Toxaris' Fontshrinker or Calibre's Font subsetting. This will create much smaller font files, and at the same time, presents an incomplete fontset to the downline user.

If you use the Adobe font obfuscation method, you can run into other issues (for example, if you intended to use the ePUB to create a MOBI file).

FWIW.
Hitch

[bobcdy]

Thanks all for the helpful suggestions. I think the font obfuscation sounds best to me - I have a post, about 2011-12, in the Font Creator forum about my problem with reducing a font (with Font Creator) to eliminate the extra glyphs and make the font smaller - ran into an odd problem in that the reduced font didn't work well at all. On some epub readers, there were odd omissions of a few glyphs so that a phrase would would have one or more blank spaces where specific glyphs didn't show even though they were certainly there when viewed with sigil. The forum moderator concluded the font reduction had caused this effect.

[JSWolf]

Sigil does allow one to remove the font obfuscation, so that is not going to work. Hitch's suggestion is the only one that will work. It will make the font files useless for anything other than that specific eBook.

[eschwartz]

Originally Posted by bobcdy

Thanks all for the helpful suggestions. I think the font obfuscation sounds best to me - I have a post, about 2011-12, in the Font Creator forum about my problem with reducing a font (with Font Creator) to eliminate the extra glyphs and make the font smaller - ran into an odd problem in that the reduced font didn't work well at all. On some epub readers, there were odd omissions of a few glyphs so that a phrase would would have one or more blank spaces where specific glyphs didn't show even though they were certainly there when viewed with sigil. The forum moderator concluded the font reduction had caused this effect.

Perhaps the glyphs were stripped but Sigil still found them from the OS font library...

[Hitch]

Originally Posted by bobcdy

Thanks all for the helpful suggestions. I think the font obfuscation sounds best to me - I have a post, about 2011-12, in the Font Creator forum about my problem with reducing a font (with Font Creator) to eliminate the extra glyphs and make the font smaller - ran into an odd problem in that the reduced font didn't work well at all. On some epub readers, there were odd omissions of a few glyphs so that a phrase would would have one or more blank spaces where specific glyphs didn't show even though they were certainly there when viewed with sigil. The forum moderator concluded the font reduction had caused this effect.

Bob:

Things have changed QUITE a lot in the last 3-4 years. I strongly recommend that you simply subset the font, using either Toxaris' program or the Calibre font subset in...POLISH ePUB, IIRC. The obfuscation method is likely what CAUSED your problem. Font Creator is not the same as these other methodologies, which are simple subtraction.

Hitch

[bobcdy]

Thanks again for the help! Because sigil can both add and remove obfuscation, the only way must be the font subset method. I'll give that a try.
Bob

[JSWolf]

Originally Posted by Hitch

Bob:

Things have changed QUITE a lot in the last 3-4 years. I strongly recommend that you simply subset the font, using either Toxaris' program or the Calibre font subset in...POLISH ePUB, IIRC. The obfuscation method is likely what CAUSED your problem. Font Creator is not the same as these other methodologies, which are simple subtraction.

Hitch

So if Charis SIL is subsetted and the name changed internally and externally, will Amazon no longer recognize it as Charis SIL and not remove it?

[Hitch]

Originally Posted by JSWolf

So if Charis SIL is subsetted and the name changed internally and externally, will Amazon no longer recognize it as Charis SIL and not remove it?

Wolfie:

Amazon has outright stated NOT to use one font: Charis SIL. I believe that you persist in this for the same reason that some people feel compelled to turn left on a "no left turn" area. Why pick the ONLY font that Amazon has expressly said not to use?

Hitch

[Freeshadow]

Originally Posted by Hitch

bobcdy:

If the gist here is to use a font in an eBook, and preclude someone down the line from being able to install/use the font without licensing same, simply use Toxaris' Fontshrinker or Calibre's Font subsetting. This will create much smaller font files, and at the same time, presents an incomplete fontset to the downline user.

Which has been my main point in the discussions about it back then.
Font subsetting is far more than mem and storage footprint saving.
THX for pointing it out again. Everybody loves having his ideas supported by a professional.