I've been hacking on shaback slowly over the last months. I'm using it "in production", so to speak, to back up my own various machines. It's nice to be able to keep only one backup copy of redundant content (like photos that I might move in bulk from one machine to another).

One of the recent improvements is to let the user choose the hash algorithm (previously, it just used SHA-1). It still defaults to SHA-1, but the more paranoid among us can opt for SHA-256 or any other algorithm supported by your Python hashlib module. Obviously it won't be able to share stored content between different runs that use different hash algorithms, but it won't hurt anything to do so and it's easy to set things up to be consistent. The hash algorithm can now be stored in the .shabackrc file too.