Sign PDF with PFX Certificate Free

Digitally sign a PDF with a .pfx or .p12 file in this browser. The private key is not uploaded. USB DSC tokens are not supported.

What this page is for

Sign PDF with PFX Certificate is a single files workstation. Certify a PDF with a certificate file you already hold, without uploading the private key. Apply a PKCS#12 / PFX digital signature to a PDF in this browser. USB DSC tokens are not supported. Use it for one action, export the result, and read the visible limit before you rely on it. If the download, copy, or figure is wrong, keep the original and try a smaller input or a related tool rather than stretching this page into a task it does not claim. OpenToolSuite will not silently upload a file to “make it work,” and it will not dress a general draft up as certified legal, tax, or hiring advice.

How to use this tool

On Sign PDF with PFX Certificate, choose the PDF, then a .pfx or .p12 file and its password. The desk shows the certificate common name and validity, writes a visible stamp on page one, and embeds a detached PKCS#7 signature. Open the download in Acrobat and read the certificate panel before you file.

Drop the PDF you are allowed to certify.
Select the PFX file, enter its password, and confirm the certificate name.
Download and verify the signature panel in a trusted reader.

How the result is made

node-forge reads PKCS#12 in the browser. pdf-lib adds a signature dictionary with ByteRange and Contents, then the SHA-256 digest of the PDF (excluding the placeholder) is signed with the private key. USB ePass / eToken dongles have no browser API and are rejected with that reason. OpenToolSuite is not a licensed Certifying Authority.

Useful scenarios

Sign a Form 16 or invoice PDF with a PFX file your CA already issued.
Certify a board resolution PDF on a machine that cannot install desktop DSC software.
Keep a private key on this device instead of uploading it to a signing SaaS.

Questions

Will a USB DSC token work on Sign PDF with PFX Certificate?

No. Browser tabs cannot talk to ePass/eToken hardware. Export or use a PFX/P12 file, or keep using the Windows token software your CA gave you.

Is the private key uploaded?

No. PKCS#12 parse and RSA signing stay in this session. Reload the tab and the key is gone.

Why does Acrobat say the signature is untrusted?

Self-signed or untrusted issuers show that warning until you trust the certificate. This desk does not replace a CCA-licensed token for MCA or income-tax e-filing that requires one.

Related tools

Use a related OpenToolSuite page for the next step instead of an upload converter.

Not CCA-licensed, not a USB token, not an e-sign under the IT Act by itself. Self-signed PFX files remain untrusted until the reader trusts the issuer.