I'm using rsync for performing daily incremental backups of my data as described on this page: http://www.mikerubel.org/computers/rsync_snapshots/
rm -rf backup.3
mv backup.2 backup.3
mv backup.1 backup.2
cp -al backup.0 backup.1
rsync -a --delete source_directory/ backup.0/
I face the problem that the backup disk is insecure, i.e., everybody in our group can access it.
Currently I decrypt the backup files before running the backup and encrypt them again afterwards. This is both insecure and inefficient.
Is ist possible, e.g., through pipes and programs like openssl / gnupg to encrypt / decrypt the backup files "on the fly"? I'm looking for a more integrated (and therefore more secure) solution than what I do currently.
What do you do to perform secure incremental backups?