This document illustrates how to digitally sign PDF documents using Acrobat Reader 11. The illustrations assume that the user already has a digital certificate. You will need the latest version of Adobe Acrobat Reader. Earlier versions of this software don t have this feature. You can download the installer from the Adobe website. Open a PDF document using Adobe Reader, then click on the Tools menu on the upper left hand corner.
Next select the Certificates option Click on the Digitally Sign Menu
A pop-up message will come up. You can put a check on the Do not show this message again if you do not want it to show every time you sign a document. Draw a rectangle over the area you want your digital signature to appear. When you finish drawing the rectangle, the Add Digital ID dialog box appears. Under I want to sign this document using: Select My existing digital ID from radio button. Then chose the radio button for A file. Click on the Next button on the bottom of the window
Click on Browse and select the folder where you have saved your Signing Certificate. Enter the password for your Signing Certificate then click on the Next button at the bottom.
Your name should now appear under the list of digital IDs. Finally click on Finish
Back at the Sign Document dialog box, enter the password for your Signing Certificate then click on the Sign button at the bottom
Adobe will then ask you to save the document. We recommend adding the word Signed so you will know that it is the signed document plus you get to keep the unsigned copy of the file. Click on Save to save the file.
Your digital signature should now appear on the document. If you get the error that the signature has problems, this is because you need to add the PNPKI Root certificates in your Trusted Certificates
How to add the PNPKI Root Certificates to Adobe's Trusted Certificates Note: This process only needs to be done one time. Double click on the digital initialize a validation process. You will get this message window. Click on the Signature Properties button The Signature Properties dialog box will appear. Click on the Show Signer's Certificate button
Next at the Certificate Viewer window, on the left hand panel, highlight the topmost option, which should say Philippine Root CA. Click on the Trust tab then click the Add to Trusted Certificates button
An Acrobat Security warning window will appear. Just click on OK At the Import Contact Settings window, put a check on Certified Documents, check on all the three options under it, then click OK
Lastly, back at the Certificate Viewer window, click on OK to finish When you click on your signature again to revalidate, it should now show that the signature is valid.