Digital Signature PDF

Add a cryptographic digital signature to your PDF using X.509 certificates. Supports PKCS#12 (.pfx, .p12) and PEM formats. Your private key never leaves your browser.

Internet connection required

Signing may need to fetch certificate chain information from your certificate issuer's server to validate the signature.

Click to select a file or drag and drop

PDF Documents

Your files never leave your device.

How It Works

1

Upload PDF

Select the PDF document you want to sign

2

Upload Certificate

Provide your .pfx or .p12 certificate file and password

3

Sign & Download

Apply the digital signature and download your signed PDF

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Frequently Asked Questions

What is a digital signature?

A digital signature is a cryptographic mechanism that verifies the authenticity and integrity of a document. Unlike a drawn signature, it uses public key cryptography (X.509 certificates) to prove the signer's identity.

What certificate formats are supported?

We support PKCS#12 format certificates (.pfx, .p12) which contain both your certificate and private key in a single encrypted file. These are commonly issued by certificate authorities.

Is my private key safe?

Yes! All processing happens entirely in your browser. Your certificate, private key, and PDF files never leave your device or get uploaded to any server.

Will the signature be valid in PDF readers?

Yes, the tool creates standard PKCS#7 detached signatures that are recognized by all major PDF viewers. For full validation, use a certificate from a trusted Certificate Authority.