Every time you make any change to the image it needs to sync the whole thing, right? Seems wasteful to me, there must be a better solution.

My impression is that cperciva is after this problem, but the wait seems indefinite.

I really doubt it. The whole point to encryption is that the storage area doesn't know anything about your files.

It doesn't. It just syncs the byte changes.

But depending on the encryption scheme, a single byte changed in the unencrypted data can result in the entire encrypted image being different.

It's 128-bit AES. I haven't had a problem yet.

technically half the bits change, on average