title_body: Fonts malformed when extracted from epub files I have an .epub from which I want to extract its embedded fonts.
  I've tried to unzip the .epub, and found the fonts in .otf and .ttf format in the OEBPS/Fonts directory; when I try to open some of them I get an error that says that they are malformed.
  
  This happens to me with all the epubs, however in the epub viewer the fonts look good.
upvoted_answer: There is a feature, font obfuscation, which prevents you from viewing/using any embedded font after  unzipping the epub. Whether this has happened in your case is unclear. However, if the epub was created in Indesign, that is likely to be the issue because Adobe Indesign obfuscates fonts when it creates epubs. 
  
  http://www.idpf.org/epub/20/spec/FontManglingSpec.html