Digital Signature
Sign a PDF with a cryptographic digital signature. It seals the document: PDF readers show who signed and warn if anything changes afterwards. Use your company or government certificate, or create one here.
Digital Signature
Add · Choose certificate · Sign
How to digitally sign a PDF
Add your PDF
Drop the file onto the tool or click Choose files.
Choose a certificate
Use your .p12 / .pfx file and password, or create a new certificate with your name.
Place and sign
Put the signature box on a page (or keep it invisible) and press Sign PDF.
Why use it
What this free tool does
Real digital signature
Standard PKCS#7 signatures that Adobe and others check.
Your certificate
.p12 and .pfx files from companies, governments and certificate authorities.
Or create one
A personal certificate made on your device.
Visible or invisible
A tidy signature box with name, date and reason.
Trusted timestamp
Optional proof of when you signed.
Private
Your key and document never leave your device.
Digital signature or e-signature?
A digital signature uses a certificate to seal the document cryptographically, so any later change is detected. An e-signature (a picture of a handwritten signature) is just part of the page.
Certificates created here are "self-signed": readers like Adobe show them as valid but not yet trusted, until the reader chooses to trust that certificate. For signatures trusted automatically, use a certificate from a recognised certificate authority.
Tip: Want to reuse your certificate? Tick "Also download the certificate" and keep the .p12 file safe.
Your files stay on your device
Most online PDF sites upload your documents to their servers. Aleynray Ai does the work inside your browser instead, on your own computer or phone.
Nothing is sent anywhere, so contracts, bank statements, IDs and medical forms stay private, and there is no waiting for uploads.
- Free, with no sign-up or limits
- No watermark
- Files never leave your device
- Works on desktop and mobile
Frequently asked questions
Do existing signatures stay valid?
Yes, the new signature is added as an update, so earlier signatures remain intact.
Is it legally binding?
Digital signatures are recognised in most countries; requirements vary, so check what's needed for your document.
Is my private key uploaded?
No. Signing happens in your browser.
Which certificates work?
RSA certificates in .p12 or .pfx files.
Is it free?
Yes. There is no sign-up, no limit on files and no watermark.
Are my files uploaded?
No. The tool runs inside your web browser and works on the file on your own device. Nothing is sent to a server, so private documents stay private.