[Borgbackup] borg cache / security aspects

[Felix Schwarz]

Hi,

I'd like to know more about security aspects of borg's cache when using
encrypted repos.

If I use an encrypted borg repo and store borg's cache right next to the
actual repo (by setting "BORG_CACHE_DIR") are there any security considerations?

So if I assume an attacker gets access to the (encrypted) borg repo and the
cache files (but not the repo key) can he deduce anything from the cache?

Background:
- I'd like to back up a somewhat bigger dataset (~2 TB) from a remote server
  with limited connectivity (100 Mbit).
- The borg repo should be on external hard drives.
- I would like to store the borg cache on the same drive so I can run the
  backup from multiple work stations. Rebuilding the cache on a new machine
  takes quite a while to rebuild (just 100 Mbit).
- I don't want to worry if someone steals the hard drive.

Thank you very much,
Felix