Re: [Duplicity-talk] Encrypted backups without secret key

[edgar . soldin]

On 11.10.2018 10:12, Mathias Rav via Duplicity-talk wrote:
> I've just started using duplicity 0.7.18.1 to backup my webserver.
> I've generated a server key on my webserver and a backup key on another
> host. The webserver encrypts the backups to the backup key and signs
> them with the server key. This seems to work, and on the host that has
> the secret backup key, I can restore the backup with duplicity.
> 
> However, during incremental backup I get an error because the secret
> backup key is not available on the webserver. Is this way of using
> duplicity unsupported? Should I be worried? I would prefer not having
> the secret key on the webserver in the event of a compromise.
> 
> Below I've included the duplicity output when backing up my database.
> FWIW I'm running Ubuntu 16.04 and backing up to B2. duplicity 0.7.18.1
> was installed with pip install --user.
> 

tl;dr

use the double key approach. create a key pair (without passphrase) for this 
machine only and encrypt against this and your personal public key (give 
multiple '--encrypt-key key-id', see man page).

reason

duplicity needs to decrypt during synchronization/verify. that can only be done 
with a matching private key. previously it was possible to run w/o a private 
key but that is error prone
  https://bugs.launchpad.net/duplicity/+bug/687295
.

regards ..ede/duply.net