I'm trying to use encfs with rdiff-backup to ensure that my backups to a remote server are encrypted. The easiest way to do this would be to use encfs --reverse - which means encfs will create a virtual encrypted file system, which I can then backup using rdiff-backup.

Except that it doesn't work. Rdiff-backup fails every time with an "input/output error" on the encfs virtual filesystem. It seems I'm not the only one with this problem, but no one has said what the problem is:

• this person reported the same issue, but was just told to use sshfs instead (see below on that);
• in this question on serverfault, one of the answers just states that "rdiff-backup seems to have trouble accessing the EncFS-reverse filesystem."
• There's an open bug report on the Debian bug tracker(bug 731413, I can't post the link) on this bug, but it's been open since December 2013 with no response.

Does anyone know what the problem actually is? Is there a workaround?

I can't use the two most commonly suggested alternatives - sshfs and then running encfs on that, or using Duplicity - as both require a much higher bandwidth connection than I have access to (Duplicity requires regular full backups).