Duplicity can often use a lot of disk space for temporary files and the archive cache. It's tempting to use the
--tempdir arguments in order to store these on the same disk where the backups are placed, but I can't find any information on whether these files can potentially expose unencrypted data.
From the man page:
The remote signatures will be encrypted if encryption is enabled. The local signatures will not be encrypted and stored in the archive dir (see --archive-dir ).
These clearly states that the signatures are not encrypted, but I'm not completely sure what information is stored in the signatures. My guess is that this includes filenames, sizes, permissions, and last modified times, but not any data from within files. Is that correct?
My bigger worry is that the temporary files are unencrypted archives which are then encrypted before being copied to the destination. I can't find any information about whether or not this is the case, and the codebase is complex enough that it wasn't easy to see exactly how the temporary files are used. Does anybody know if they are used to store unencrypted archives?