Do these two files match?
Drop a file on each side. Each becomes four Odù — three from the file, one a checksum. Play them and compare by ear, or read them down a phone.
Everything stays on your machine. The file is hashed here in
the browser and nothing is uploaded. Nothing is stored, either — reload and
it is gone.
First file
Second file
What this catches, and what it does not. Three bytes is 24
bits, so a computer can find two files with the same fingerprint in seconds.
This tells you a download did not truncate, a file did not rot, and you sent
the take you meant to. It is not a defence against someone who wants
the fingerprints to match — for that, compare the whole SHA-256.
Same thing at a terminal:
odu fingerprint FILE — or
sha256sum FILE and read the first six hex characters.