CastNymCastNym

CastNym content check

Check a piece of content

Paste the link you were given, or drop the file. You get one of three answers back: verified, not verified, or unknown. No account, and nothing to sign up for.

We read the identifier out of the link and look that up. We do not open the link and we do not download whatever is at the other end.

Drop one file here

The file stays on your device. Your browser calculates its SHA-256 fingerprint, and only that fingerprint is used for the lookup. We never receive the file or its name.

Maximum file size: 5 GiB. Any file type is supported.

How a check works

  1. We read the identifier out of your link, or your browser fingerprints your file on your device.

  2. Two separate checks run: CastNym's own record, and the signature over the exact bytes.

  3. You get one of three answers: verified, not verified, or unknown.

Check our signatures yourselfEvery verdict rests on an Ed25519 signature anyone can verify against our published public keys, without asking us.Our public keys