If you are the author or internal reviewer of a document, you can certify a document by applying a certifying signature. Certifying a document uses your digital ID and security settings to encrypt a file.

To certify a PDF document:

1. Do one of the following:
• Select the Digital Signatures  tool.
• Select Document > Digital Signatures > Sign Document.
2. Drag open a rectangle on the page to place a digital signature.
3. Select the Certify Document option.



4. In the Save as Certified Document window, select an allowable action from the drop down menu, and then click OK. If you want the signature protected so it cannot be cleared, check the box for Protect (Lock) the Certifying Signature so that it cannot be cleared or deleted by anyone.
5. Select PDF Self-Sign Security and click OK.
6. Click OK again and in the Self-Sign Security window enter your password. Select an appearance (optional) and click Save or Save As.

Related info: Nitro Pro 5 Help

Using digital signatures in PDF
How to digitally sign PDF files
How to view & validate signatures in PDF
Securing and locking PDF files