MobileRead Forums - View Single Post - Warning: resource oebps/font/Agaramond-regular.otf cannot be decrypted

prepress · 10-13-2010, 02:57 AM

We've found out that this warning didn't appear when converting a file in Calibre 0.6.40, but all newer versions after 0.6.40 produce this error in combination with epubcheck 105.

Since our customer uses epubcheck to validate the epubs and they don't want any warnings or errors in the final verdict of epubcheck, we're forced not to update calibre and stick with 0.6.40.

This is what epubcheck support says:

<<<<<<<
There is an embedded font in the package that is obfuscated using Adobe's method. I am not familiar with their font mangling algorithm but looking at the epubcheck source code I see that it is expecting the algorithm to be declared as "http://ns.adobe.com/digitaleditions/enc". The algorithm in the sample is declared as "http://ns.adobe.com/pdf/enc#RC".

Probably this font will not be displayable in any EPUB readers, but I am not convinced that the EPUB is invalid just because epubcheck can't decrypt the font.

Algorithm URL "http://ns.adobe.com/pdf/enc#RC" is correct for Adobe obfuscation. I think this warning is given any time we hit an encrypted resource, just to let users know that we did not validate that resource in any way. Being a warning, it does not mean that EPUB is invalid.
>>>>>>>>

Now my question is this:
Howcome new versions of calibre, after 0.6.40, have changed something so embedded fonts are decrypted? Is it possible to revert this so this warning won't show up again?

Thanks for your help.

10-13-2010, 02:57 AM	#2
prepress Junior Member Posts: 3 Karma: 10 Join Date: Sep 2010 Device: none	Warning after calibre 0.6.40 resource cannot be decrypted We've found out that this warning didn't appear when converting a file in Calibre 0.6.40, but all newer versions after 0.6.40 produce this error in combination with epubcheck 105. Since our customer uses epubcheck to validate the epubs and they don't want any warnings or errors in the final verdict of epubcheck, we're forced not to update calibre and stick with 0.6.40. This is what epubcheck support says: <<<<<<< There is an embedded font in the package that is obfuscated using Adobe's method. I am not familiar with their font mangling algorithm but looking at the epubcheck source code I see that it is expecting the algorithm to be declared as "http://ns.adobe.com/digitaleditions/enc". The algorithm in the sample is declared as "http://ns.adobe.com/pdf/enc#RC". Probably this font will not be displayable in any EPUB readers, but I am not convinced that the EPUB is invalid just because epubcheck can't decrypt the font. Algorithm URL "http://ns.adobe.com/pdf/enc#RC" is correct for Adobe obfuscation. I think this warning is given any time we hit an encrypted resource, just to let users know that we did not validate that resource in any way. Being a warning, it does not mean that EPUB is invalid. >>>>>>>> Now my question is this: Howcome new versions of calibre, after 0.6.40, have changed something so embedded fonts are decrypted? Is it possible to revert this so this warning won't show up again? Thanks for your help.