What is the difference between a visual signature and a digital signature?

A visual signature is just an image stamped on the PDF. A digital signature is a cryptographic proof that verifies the signer's identity and proves the document was not modified after signing.

Can I use my own company certificate?

Yes — upload your .pfx or .p12 certificate file. Docukit will use your certificate's private key (entered via password) to sign the document. The private key never leaves your browser.

Will Adobe Acrobat show the signature as valid?

With a CA-issued certificate: green "Signature is valid" checkmark. With a self-signed certificate: yellow warning with "Identity not verified" but integrity is still confirmed.

Is my private key secure?

Yes — your private key exists only in browser memory during signing and is immediately garbage-collected afterward. It is never stored or transmitted.

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Digitally Sign PDF Online for Free

Add a real, verifiable cryptographic digital signature to PDF documents using PKCS#7 / PAdES standard. Generate a self-signed certificate or use your own CA-issued certificate.

Files never uploaded No account required Unlimited use, free forever WebAssembly-powered

Drop your file here, or click to browse

The PDF you want to sign

Or press Ctrl+V to paste

Certificate

Common Name (Your Name) *

Organization (optional)

A self-signed RSA-2048 certificate valid for 1 year will be generated. The PDF will contain a cryptographically valid PKCS#7 signature. You can also download the certificate as a .p12 file.

How to Digital Signature PDF

Choose your certificate

Generate a free self-signed certificate in-browser, or upload your existing .p12/.pfx certificate file.
Upload and configure

Upload your PDF, optionally place a visible signature image linked to the digital signature field.
Sign and download

Click "Sign & Download" — your PDF is cryptographically signed per PKCS#7 / PAdES standard.

Features

PKCS#7 / PAdES standard digital signatures
In-browser RSA-2048 key & certificate generation
Upload existing .p12/.pfx certificates
SHA-256 hash of document content
Private key never stored or transmitted
Verifiable in Adobe Reader / Acrobat
Combine visible + cryptographic signature

Frequently Asked Questions

What is the difference between a visual signature and a digital signature?: A visual signature is just an image stamped on the PDF. A digital signature is a cryptographic proof that verifies the signer's identity and proves the document was not modified after signing.
Can I use my own company certificate?: Yes — upload your .pfx or .p12 certificate file. Docukit will use your certificate's private key (entered via password) to sign the document. The private key never leaves your browser.
Will Adobe Acrobat show the signature as valid?: With a CA-issued certificate: green "Signature is valid" checkmark. With a self-signed certificate: yellow warning with "Identity not verified" but integrity is still confirmed.
Is my private key secure?: Yes — your private key exists only in browser memory during signing and is immediately garbage-collected afterward. It is never stored or transmitted.