Is there a way to have rolling incremental backups?

My planned backup scenario is to have rolling incremental backups, based on one full upload at the beginning, with the ability to delete things older than X days. Having the backups gzipped and encrypted is a most welcome bonus, but not having to upload all the files every now and then (as in, performing a new full backup) is a requirement.

I did some research and ran a couple of test scenarios, but I’m still not 100% sure whether there is a way to obtain this behaviour with duplicity; it seems that any space recovery (in the form of removing backups older than, say, 30 days) requires that a full backup is done first, and doing that requires re-uploading all of the data over the network from scratch – or can duplicity re-use previously-uploaded volumes to construct a new full backup?

(Basically, it seems what I’d love to have is rdiff-backup with encryption, and I’m wondering whether duplicity can work in this manner…)