rsync hashing / collision handling?

[Karl O. Pinc]

On 10/02/2012 03:58:04 PM, Andrew Pennebaker wrote:
> Have recent versions of rsync considered using a more robust
> implementation
> of file change monitoring, like Dropbox
> <https://www.dropbox.com/help/8/en> does?

The above link says Dropbox does a "binary diff".
How are you proposing to do a binary diff,
which implies a bit-for-bit comparison,
when the 2 copies of the data to be compared
are on different machines?

Regards,

Karl <kop at meme.com>
Free Software:  "You don't pay back, you pay forward."
                 -- Robert A. Heinlein