Attested.
Hash a file in your browser and receive a sealed record of who submitted it and when. Anyone can check the seal against our published keys, with no account and no upload.
Your file stays with you
Your browser hashes the file. Only the SHA-256 fingerprint is sent, never the file itself.
Two signatures
This browser's key signs first. ContentProof then countersigns who, what and when. The service never holds your key.
Verify anywhere
Checks run in the browser against the published keys. No account is needed to verify.