If you're exceptionally paranoid, an adversary with access to your encrypted .dmg on Dropbox may be able to deduce sensitive information by analyzing the change

If you're exceptionally paranoid, an adversary with access to your encrypted .dmg on Dropbox may be able to deduce sensitive information by analyzing the changes in the file. It doesn't necessarily mean your data is at risk, but maybe it could point your adversary to the bits of information you change most often. This would be true with any encrypted file using any algorithm. That said, unless you've gained the attention of a TLA (that's Three Letter Agency), it's a minuscule risk and I really wouldn't worry about it.