freebsd-ports/misc/xdelta/pkg-descr

Xdelta provides the ability to generate deltas between a pair
of files and later apply those deltas.  It operates similar to
the diff and patch commands, but works on binary files and does
not produce a human readable output.

Xdelta has three subcommands, delta, patch, and info.  Delta
accepts two file versions and produces a delta, while patch
accepts the original file version and delta and produces the
second version.

WWW:	http://code.google.com/p/xdelta/