xdelta - Binary delta generator

Xdelta is a program designed to compute changes between files.  These changes 
(deltas) are similar to the output of the "diff" program in that they may be 
used to store and transmit only the changes between files.  However, unlike 
diff(1), the output of xdelta is not expressed in a human-readable format.

Xdelta uses a fast, linear algorithm and performs well on both binary and 
text files.