Sign PDF (Certificate)
Apply a cryptographic digital signature to your PDF using a PKCS#12 certificate. The signed file is tamper-evident and verifiable in Acrobat and other standards-compliant readers.
How to sign a PDF with a certificate
Apply a cryptographic digital signature to a PDF using a PKCS#12 (.p12 / .pfx) certificate.
Open Sign PDF (Certificate)
Go to makemypdf.com/sign-pdf-cert.
Upload your PDF
Drop the document you want to sign.
Upload your certificate
Provide a PKCS#12 (.p12 or .pfx) file that contains your private key and X.509 certificate.
Enter the password
Certificates are password-protected. Enter the password for your .p12 / .pfx bundle.
Add optional metadata
Reason (e.g. "Approved") and Location are embedded in the signature for audit purposes.
Sign and download
The signed PDF is returned with a cryptographic signature field that any PAdES-aware reader can verify.
Frequently asked questions
How is this different from the regular Sign PDF tool?
The regular Sign PDF tool places a drawn image of your signature on the page — it looks signed but has no cryptographic proof of identity or tamper-resistance. This tool applies a real digital signature using your PKCS#12 certificate, producing a PDF that Acrobat and other readers will verify and flag if anyone modifies it after signing.
Where do I get a PKCS#12 certificate?
From a trusted certificate authority (CA) — examples include GlobalSign, DigiCert, Sectigo, or government-issued certificates (eID). Self-signed .p12 files work too, but only trusted CA signatures will show as "verified" without a manual trust decision.
Is my certificate password stored?
No. Your .p12 file and password are held in memory only for the duration of the signing operation and discarded immediately after. Nothing is persisted to disk or logged.
What signature standard is used?
We produce PAdES-compliant signatures (PDF Advanced Electronic Signatures), the ISO 32000 / ETSI standard used by eIDAS-qualified signing flows across the EU and by US / UK federal agencies.