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Sign PDF

Your .p12 or .pfx and its password; a PDF every reader verifies, signed by you.

More free conversions, where you upload. The Fylane extension does the same work inside any upload form, on its own free share every day.Add to Chrome

How to sign PDF

  1. Drop the PDF and your .p12 / .pfx certificate.
  2. Type the certificate password; add a reason if you like.
  3. Press Sign and download the signed PDF.

What happens to your file

OpenSSL opens your PKCS#12 with the password, the PDF gets a signature field with a byte range and room for the signature, the two byte ranges are hashed (SHA-256) and signed into a detached CMS with your key and certificate chain, and the signature is written into the document — the shape Adobe Reader, pdfsig and every validator verify.

Fylane holds no certificate and signs nothing of its own: without your .p12 there is no signature. A self-signed certificate verifies as valid but untrusted until the reader trusts it. The password and key live only for the job.

Questions

Where do I get a .p12?

From your organisation’s certificate authority, a commercial CA, or — for testing — OpenSSL: a self-signed one takes two commands.

Is this the same as an e-signature service?

It is the cryptographic signature those services embed, without their identity checks or audit trail. What it proves is that the holder of the certificate’s key signed these exact bytes.

Timestamps and long-term validation?

Not yet: no timestamp authority is contacted. The signing time is the platform clock, stated in the signature.

Do it once, not on every form

Fixing a file here means downloading it and going back to the form. The Fylane extension does this work inside the form instead, on the file you already have.

And it keeps the result. The next application that asks for a résumé, a cover letter and a photo fills all three from one tap, each one refitted to what that site accepts.

Your files stay in the browser, encrypted, on your machine. Nothing is uploaded to keep them and nothing is sent anywhere to fill a form.

Filmed from the extension: three upload fields on a job application, filled from one tap.

Add to Chrome — freeWhat it does

Do this in code

curl -X POST https://api.fylane.dev/v1/jobs \
  -H "Authorization: Bearer $FYLANE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "file_id": "<file id>",
    "operation": "pdf.sign",
    "options": {
      "password": "<password>",
      "reason": "Approved",
      "timestamp": "none",
      "visible": "yes",
      "file_ids": [
        "<second file id>"
      ]
    }
  }'

The same operation, pdf.sign — A real digital signature (PAdES-style, adbe.pkcs7.detached, SHA-256) with your own PKCS#12 certificate: two inputs — the PDF and the .p12 / .pfx — plus `password`; `reason`, `location`, `visible` stamp, `timestamp` (none, sectigo or freetsa — an RFC 3161 token from a free authority over HTTPS, on the Batch lane). The platform signs nothing on its own behalf. Upload first with the quickstart; every option is on the operations page. 500 free credits a month, then $5 per thousand.