Verify PDF signatures

Digital signatures are meaningless unless you can verify them for authenticity. When you are certain a document came from a user who signed a PDF, you can accept the validity of the signature. If you are not sure of where a signed document came from, you need to acquire a public certificate and use it to verify a signature.

To verify signatures:

1. Do one of the following:
• Left-click on a signature.
• Select the Show/Hide Document Panel toolbar button, followed by the Signatures panel button.
2. Examine the verification status. If you open the Signatures panel, the status is reported as Validity Unknown or Valid. If you left-click a signature, the Self-Sign security - Validation Status window opens. The window reports the status as Unknown or Valid.

3. Examine the signature properties. If you left-click a signature field, click Properties in the Self-Sign security - Validation Status window. You can view information about the signature.
4. If a signature is not valid and you know that the signature is authentic, click Verify Identity in the Self-Sign Security - Signature Properties window.
5. In the Verify Identity window, click Add to List. When you click Add to List you are telling Nitro you trust the signature from this signer. All subsequent files signed by the same person will be reported as Valid.

Related info: Nitro Pro 5 Help

Digital signatures in PDF files
Digitally signing a PDF file
View & validate signatures in PDF files