File hash
Drop a file, get its MD5, SHA-1, SHA-256 and SHA-512 — computed locally, the file never leaves your browser.
/tools/file-hash lets you drag a file into the drop zone (or pick one through the file dialog) and compute its MD5, SHA-1, SHA-256 and SHA-512 in one go.
The file is read into memory through FileReader, then passed to crypto.subtle.digest for the SHA-* digests and to the bundled MD5 implementation. Nothing is uploaded — there is no progress bar over the network because there is no network call. That’s the privacy angle: many “online file hash” calculators require you to upload the file to their servers, which is exactly the wrong thing to do for sensitive content.
Useful for verifying downloads against a published checksum, comparing two suspiciously-similar files, or confirming that the build artefact you just pulled matches the one in the release notes.
Limit: files load fully into memory, so very large files (multi-GB) may strain the tab. SHA-256 of a 200 MB file is roughly half a second on a modern laptop.