JDIFF is a program that outputs the differences between two binary files,
either in binary format or human readable format (detailed or summarized).
JPTCH can then be used to reconstruct the second file from the first file.

Possible applications include incremental backups, synchronising files
between two computers over a slow network, and others.

JDIFF tries to find a minimal set of differences between two files using
a heuristic algorithm with constant space and linear time complexity.
This means that accuracy is traded over speed.  JDIFF will therefore, in
general, not always find the smallest set of differences, but will try
to be fast and will use a fixed amount of memory.