A GnuPG backend could be useful to sign files you upload on the fly, and allow the option of verifying signatures on file reads. It could include a command to provide if a signature exists, and, if so, information about the signature.
So like if you have a remote abc:, and you uploaded a file 123.txt, it would look like this:
abc:123.txt
abc:123.txt.sig
Indeed, I'd even go further if this is implemented and also provide an option for encryption using GnuPG. I know the rationale behind not using it for encryption was that key management is then a huge issue and there might be a loss of data. But it might be okay if it's tucked inside advanced options or something? idk...thoughts?