Generate and Verify a Checksum File (SHA256SUMS)

Generate a checksum file (SHA256SUMS…) for a batch of files, or check files against a reference list, right in your browser.

Drop one or more files

their hash is computed locally

100% local processing, nothing is uploaded

How does it work?

Two modes. Generate: choose an algorithm, drop several files, and get a checksum file (SHA256SUMS format from the GNU tools) to download. Check: paste (or drop) such a checksum file, then drop the corresponding files: each one is compared with its reference line.

The format is compatible with the Linux sha256sum -c command. Everything is computed locally; no file is uploaded.

Examples

Publishing hashes

You distribute 5 files: generate a single SHA256SUMS containing 5 “hash name” lines. Your users will check them all at once.

Checking a batch

Drop the SHA256SUMS then the 5 files: the tool shows “✓ matches” or “✗ different” for each one, and flags a file missing from the list.

Frequently asked questions

Is the format compatible with sha256sum?
Yes. The generated file follows the GNU coreutils convention (“hash␣␣name”), readable by “sha256sum -c”. Reading also accepts the “BSD” format (ALGO (name) = hash).
How are the files matched?
By their name. Each dropped file is matched with the line of the checksum file bearing the same name, then its hash is recomputed and compared.
Is my data sent anywhere?
No. All the computation happens in your browser, in JavaScript and WebAssembly. Your text, your files and your hashes never leave your device: no network request is made during hashing, and nothing is stored on a server.

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