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How to Sign a PDF with a PFX or PKCS#12 Certificate

A PFX (also called PKCS#12, .pfx or .p12) file holds your signing certificate and its private key, protected by a password. Here is how to sign a PDF with it in Dragdox.

Before you start

  • Your .pfx or .p12 file and its password. The certificate must be valid today and allow digital signatures.
  • Dragdox installed on Windows or Ubuntu/Debian.

Steps

  1. Windows only: open Settings → Keystore and turn on PFX Store. It is already on in Linux.
  2. Click Open PDF and choose your document.
  3. Click Begin Sign and drag a rectangle where the signature should appear, or pick an existing signature field.
  4. In the certificate window click Browse PFX File, select your file, click Choose and enter its password. You get three attempts.
  5. In the signature appearance window set the rendering mode, signature permissions (certification level), reason, location and options such as Green Tick. LTV and Timestamp need Premium.
  6. Click Sign and choose where to save the signed copy.
  7. Open the signed PDF to check it — see Verify a PDF digital signature.

In the free version the signed copy has a light Dragdox watermark on every page. Premium removes it from new output; it never changes files you signed earlier.

Keep your certificate safe

Anyone with your PFX file and its password can sign as you. Do not email or upload it, and do not share the password.