WebDAV client side encryption?

[snakechaser]

Hi all,

I found some (genuinely) free cloud service, offering 1000gb for life. It only allows WebDAV backup jobs, all working fine with the qnap's WebDAV app installed etc. The cloud company is legit and all, but doesn't offer two-factor login. So, for some of my personal / business-related files, I'm trying the "clientside encryption" option. Some safety and privacy doesn't hurt, right? So the backups work fine, files get uploaded. The (encrypted) files/folders are indeed unreadable when I download them from the cloud.

The cloud service is simply meant as a last-resort backup. I don't need quick access to the files. It's just intended as a backup of a backup.

Thing is, how do I restore (and decrypt!) these files? The WebDAV app offers a restore tab, I get that. But I'm not sure what other restore options are available. In case I need to restore the files, is the WebDAV app the only possible way to restore the files? I searched around a bit, installed openssl (w10 x64), tried to decrypt random files using the 'commands' given by the webdav app (but that gave errors).

I'm fine doing a full restore if needed using the WebDAV app, but what if that app gets removed one day? What if I switch to synology? What options are there to restore the encrypted files from the cloud?

I'm a complete noob on unix, but I know just enough to launch a ubuntu live cd, open up a terminal, copy some commands from a random tutorial. Would the
"openssl enc -d -aes.... etc" command work in all (future) unix distro's?

Basically, I'm just curious if it is wise to use the "clientside encryption" function, and how I would be able to decrypt the files in the future (if needed). Any ideas?

Thanks!