NightOwl PDF
Check a PDF’s digital signatures
See who digitally signed a PDF, whether each signature is valid, and whether the file was changed after signing.
Open Check a PDF’s digital signatures
What you can do
- Each signature’s signer, certificate, issuing authority and signing time.
- Whether the document was changed after it was signed.
- Whether the certificate chains to a trusted authority: India’s Controller of Certifying Authorities (CCA) and Adobe’s trust list.
- Whether the certificate was revoked, asked of the authority that issued it.
- A signature from an untrusted certificate, or one whose time comes only from the signer’s computer, is said plainly.
How to do it
- Open Check digital signatures and choose a signed PDF.
- Read the result for each signature.
- Open the details of any signature for its certificate.
Good to know
- The PDF stays on your computer. To ask whether a certificate was revoked, NightOwl sends only that certificate to the authority that issued it, never the document. Private mode skips that question.
- A signature drawn or pasted as a picture is not a digital signature and cannot be checked.
Questions
Will adding comments in NightOwl break a signature?
No. Comments on a signed PDF are added after the signature, so the signature stays valid.