Sign a PDF with your digital certificate
Add a certificate-based signature in your browser. Your certificate, its password and the PDF never leave your device.
- Your files are never uploaded
- Processed on your device
- Works offline
- Free, no sign-up
Drop your PDF files here
A PDF and your certificate (.p12 or .pfx) · up to 2 files, 500 MB each
or paste with Ctrl+VLive preview
Settings
The password of your .p12 or .pfx file. It is used only in your browser.
How it works
Add the PDF and your certificate
Your certificate is a .p12 or .pfx file.
Type its password
And an optional reason and place.
Download
Open it in Adobe Acrobat to see the signature.
What a digital signature does
It locks the file: if anyone changes the PDF later, PDF readers show that the signature is no longer valid. It also shows the name on your certificate.
Whether a reader shows the signer as trusted depends on who issued your certificate. Certificates you made yourself show as not trusted.
Limits
RSA certificates are supported. The signature has no online timestamp, because getting one would send data to a timestamp server. The time comes from your computer's clock.
Signing rewrites the PDF, so earlier digital signatures in the file stop being valid.
Why it matters that nothing is uploaded
Your certificate's private key proves your identity. Other websites ask you to upload it; here, it never leaves your device.
Private
Your file is processed inside your browser with node-forge (BSD-3-Clause) and pdf-lib. The certificate and its password are used only in your browser's memory. It is never uploaded, and nothing is saved after you close the page.
Questions
Are my files uploaded?
No. The tool runs inside your browser, so your files are opened and changed on your own device. They are never sent to us or to anyone else.
Where do I get a certificate?
From your company, a government ID service or a certificate authority. Some e-ID cards and tokens cannot export a .p12 file; they need their own software.
Does it work in Adobe Acrobat?
Yes. Acrobat shows the signature in its Signatures panel.
Is it free?
Yes. Free to use, with no sign-up, no watermark and no daily limits.
Related tools
More free tools that run on your device. No uploads