KMAC256 File
Compute the KMAC256 hash of any file. Streams the file with a 64-byte tag. Requires a key.
Calculate the KMAC256 hash of a file. Free, offline, runs entirely in your browser. Read more Show less
What is KMAC256 file hashing?
KMAC256 is a keyed message authentication code from NIST SP 800-185. It produces a 64-byte tag that proves the file was created by someone with the same key. Use it for authenticating large downloads when both sides share a secret. Enter your key above.
How to use
Drag a file into the box, click to select one, or paste from the clipboard. Enter the shared key in the field above. The tool streams the file in chunks and computes the hash as it reads. You can also enter a file URL; the server must allow cross-origin requests.
FAQ
Are my files uploaded anywhere?
No. The file never leaves your device.
How large a file can I hash?
Any size your browser can open. KMAC256 is streamed in chunks, so memory use stays flat.
Why does my hash differ from another tool?
Confirm the file is byte-identical and the other tool is reading it in binary mode. Text modes can alter line endings.
Command line equivalent
# Node with hash-wasm
node --input-type=module -e "import { kmac256 } from 'hash-wasm'; import fs from 'fs'; const k = new TextEncoder().encode('mykey'); const b = fs.readFileSync('myfile.bin'); console.log(await kmac256(k, b, 512, ''));"The server must allow cross-origin requests (CORS). If it doesn't, download the file and use the File tab.