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PDF Signing Guide
Adobe Acrobat Reader DC is the most common free tool for signing PDFs with a USB token-based Digital Signature Certificate. Here's the complete process.
Make sure Adobe Acrobat Reader DC is installed, and your DSC token's drivers are set up before you start.
Plug your Class 3 DSC token into your computer and wait a few seconds for it to be detected.
Use Adobe Acrobat Reader DC to open the document.
From the top toolbar, click Tools, then choose Certificates, this switches the toolbar to signing mode.
Click the Digitally Sign button, then click and drag on the PDF to draw the signature field where you want it to appear.
Adobe will show the certificates it can detect, select your DSC from the connected token. If it doesn't appear, see the troubleshooting section below.
You'll be asked for your token's password/PIN, this authorizes the signing operation using your private key, which never leaves the token.
Optionally customize how your signature appears on the page, then click Sign.
Adobe will prompt you to save, the signed PDF now contains your certificate-based signature and a tamper-evident seal.
This usually means either the token drivers aren't installed correctly, or Adobe isn't configured to trust your Windows Digital IDs. Try unplugging and reconnecting your token, confirm it's detected in your token management tool (like the WD Proxkey utility), and check Adobe's Preferences > Signatures > Identities & Trusted Certificates settings.
If the issue persists, it's often a driver version mismatch, reinstalling the latest token driver from your CA or token manufacturer resolves most detection issues.
Whether it's a driver issue or you need a new Class 3 certificate altogether, we can help sort it out.
No, the free Adobe Acrobat Reader DC fully supports certificate-based signing with a USB token.
Your DSC's private key is stored securely on the USB token hardware and never leaves it, the PIN authorizes the token to perform the signing operation internally.
Yes, once your token is plugged in and detected, you can sign multiple PDFs without re-entering your PIN each time, depending on your token's session settings.