I've been trying to recover some fonts from an epub created with InDesign. I tried both Adobe and IDPF algorithms (I used this source). I tried obfuscating and undoing it with a font outside InDesign and it worked.
In my searches I found out that InDesign compress the fonts. What I wanted to know is how can I uncompress theses fonts in android. I tried using InflaterInputStream to uncompress it, but with no sucess causing a
IOException caused by: java.util.zip.DataFormatException: data error
I tried this approach because the font inside the epub file has 11kb and the original font has 253kb.
Well, tried to be as clearer as I could, any doubts please ask.
One piece of information that may be helpful is that InDesign CS5 now subsets fonts that are included in epub documents. The 253kb to 11kb size difference may simply be compression, but it seems somewhat unlikely.
So you may find that, even after extracting the font, it is not very helpful to reuse as it will be missing key characters that were not used in the ePub.