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How to Use a CAC Card to Sign PDFs in Acrobat DC
Question details
The user wants to configure and use a Common Access Card (CAC) to digitally sign PDF documents securely.
- Product
- Adobe Acrobat DC
- Device & OS
- not provided
- Scenario
- Signing official PDF documents securely using a physical CAC card after upgrading to Acrobat DC.
- Observed behavior
- The user needs to successfully configure Acrobat DC to recognize and apply the CAC digital certificate for document signing.
Ensure your physical CAC reader is properly connected to your computer and that you have your current CAC PIN ready before configuring your PDF software.
Configure CAC Middleware and Acrobat Digital Signatures
Update your CAC reader drivers and configure Acrobat DC to properly recognize the operating system's certificate store.
To sign documents using a CAC, Adobe Acrobat DC needs to communicate with the smart card through middleware. If the middleware or drivers are outdated, Acrobat will not detect your certificates.
Download and install the latest CAC middleware (such as ActivClient) and card-reader drivers for your specific operating system.
Open your system settings to remove any old or conflicting smart card drivers and outdated certificate entries that might interfere with the new setup.
Insert your CAC into the reader and open your operating system's certificate manager to verify that the certificates are actively recognized.
Open Acrobat DC, navigate to Edit > Preferences > Signatures. Under 'Identities & Trusted Certificates', click 'More' and ensure your CAC certificate is selected as the default signing credential.
Restart Adobe Acrobat DC, open a sample PDF, select the 'Certificates' tool, and attempt to digitally sign the document to confirm the setup works.
Easily Sign PDFs Using Digital Certificates in WPS Office
If you are facing configuration issues with Adobe Acrobat DC, WPS Office provides a lightweight, highly compatible PDF reader and editor that seamlessly integrates with your system's digital certificates for secure document signing.
- 1. Open your PDF in WPS Office: Launch WPS Office and open the PDF document you need to sign.
- 2. Access the Protect tab: Navigate to the 'Protect' tab on the top ribbon and click on the 'Sign Document' or 'Digital Signature' option.
- 3. Select your certificate: Choose your CAC or digital certificate from the list of system-recognized certificates that appears on the screen.
- 4. Apply the signature: Draw the signature box where you want it to appear, enter your PIN if prompted by the smart card middleware, and save the signed PDF.
Frequently Asked Questions
Why is Acrobat DC not recognizing my CAC certificate?
This usually happens if your CAC middleware is outdated or if Adobe Acrobat is not configured to look at the Windows Certificate Store. Updating your middleware and adjusting Acrobat's Identity preferences usually resolves this.
Can I use a CAC card to sign PDFs on a Mac?
Yes, but you must ensure you have the correct macOS-compatible middleware (such as CACKey or PKard) installed and configured, and that your PDF software is set to access your keychain for certificates.
Do I need specific software for my CAC card reader?
Yes, a smart card reader alone is not enough. You must install specific middleware so that your operating system can securely communicate with the microchip on your CAC.
How do I clear old CAC certificates from Windows?
Open the Windows Certificate Manager by typing 'certmgr.msc' in the run dialog, navigate to the Personal > Certificates folder, and safely delete any expired or old certificates associated with your previous cards.
