There a standard way to assign (PGP) EPUB eBooks?

A way to use digital certificate, like in the PDF's certificate-based signatures, but not PDF.


Theoretically, you could add a signatures.xml file to the epub. However, I don't know of any epub app that actually supports this feature.

I.e., you'd also have to provide readers with a standalone app that validates the checksums.

It'd probably be easier to generate an MD5 checksum for the whole epub.

  • Yes, even without concrete examples or benchmark-applications, this is a good clue. The cited W3C standard, XML DSIG Core offers PGP (!). About MD5, in nowadays it is not valid for secure assign neither integrity, for checksum we must use "modern" SHA256, SHA3, etc. – Peter Krauss Jun 2 '18 at 15:22
  • The updated spec 3.1 says "Each Signature in the signatures.xml file identifies by IRI the data to which the signature applies, using the [XML DSIG Core] Manifest element and its Reference sub-elements. Individual contained files might be signed separately or together" – Peter Krauss Jun 2 '18 at 15:27
  • Update, ref. may 2019. See the Spec v3.2, section - Digital Signatures File (signatures.xml) – Peter Krauss Jan 4 at 18:28

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