Hi Kovid,
First of all, thank you so much for Calibre—I use it all the time (and have for nearly a decade now) and love it so much!
I'm a small book publisher, and I use Calibre most often to clean up my converted epub files. I start with my fully laid out print book in InDesign, then when that's ready, I export it to en ePub, then use Calibre to clean up the code. I used to have lots of errors with embeddable fonts many years ago, but the programs and ereaders have all improved so much, this hasn't presented any problems in a long time. Until now...
I followed my usual process for a new release I'm working on. As a best practice, I do not put DRM on any books we release since it causes issues with audience/reader availability. I fixed up the book in Calibre, and when I went to upload it to my various distribution channels, some worked just fine and as expected, and at others I got this error:
"You have submitted an encrypted ePub. Encryption is not fully supported across the publishing industry and may delay or prevent publication at certain digital stores."
Baffled, I went to try to troubleshoot, and downloaded the DeDRM plugin (see this support thread for details:
https://github.com/noDRM/DeDRM_tools/issues/175). Some members in that forum were able to help me suss out that the error seems to be connected to the embedded fonts from Adobe (after looking at the encryption.xml file, which I also copied into that thread). After looking at that, it doesn't look like the plugin is actually isn't related, however it looks like something called "Font_decrypt" is—and that doesn't appear to be connected to any other plugin, so I'm wondering if it's a Calibre thing, and if so, how can I troubleshoot this (both for this edition, and for my future process) so we don't come up on this again?
Thanks so much for your help, and please let me know if you need any more information. Your help and your hard work on this program is SO appreciated.
Cheers,
Thea