Verify a document
A CertifiedCopy PDF carries a page-hash chain and, if its maker asked, the notary's attestation. Drop the file here and the notary says whether this copy is the one it witnessed. The document is read in memory and forgotten; nothing is stored.
This link names a document digest; the verdict says whether the file matches it.
Checking a document needs an account. Sign in, then come back to this page — the link above still names the document. Only the notary can open an attestation, so only the notary can answer, and it answers for an account rather than for whoever happens to be asking.
Up to 20 MB on the Free tier; more on a paid one.
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What the verdict means
- Witnessed. The notary opened the attestation this copy carries and it names exactly this document's text: every page, in order, as the notary saw it. Nobody else can open the attestation, which is why this check is the notary's and not the page's.
- No attestation. The document is a CertifiedCopy export whose maker did not ask the notary to witness it. Its own chain of proof still holds; the notary simply was not there.
- Not witnessed. The attestation does not name this document: the text was altered after it was witnessed, or the attestation was moved from another document. The reason is stated.
- Could not be checked. The notary did not answer. The attestation is unchecked, not false; try again later.
Check the chain of proof by hand
§4 of every certificate names the steps. The source file's SHA-256 is compared with
shasum -a 256; the document's own digest is the final link of the page-hash chain
printed in §2, computed over each page's text and the previous page's digest, so any change to
any page changes it. The notary's published verifying key has id 11b259eec35dafc8.