Certificate Signing Online — Free & Instant

Sign PDF documents with a digital certificate (PKCS) online for free. Legally valid, secure signing.

📜Sign with Cert — Free, No Signup

How to certificate signing in 4 steps

Upload your PDF file
Upload your digital certificate file (.pfx or .p12)
Enter your certificate password
Download the digitally signed PDF with a verifiable certificate

Why certificate signing your PDF?

Apply a cryptographic digital signature using your own certificate for legal binding. Required for official document submission to courts, tax authorities, and regulated industries.

Tips for best results

PFX/P12 certificates are issued by authorised Certificate Authorities (CAs)
DSC (Digital Signature Certificate) holders in India can sign directly with their certificate
The signed PDF shows a blue ribbon in Adobe Reader when the certificate is trusted

Related PDF tools

🔒Protect PDF 🔓Unlock PDF ✍️Sign PDF 💧Add Watermark

Frequently asked questions

Is Certificate Signing free to use?+

Yes. Certificate Signing is free for files up to 25MB with up to 3 tasks per day. Upgrade to Pro for unlimited use.

Do I need to create an account?+

No account is needed for free tasks. Sign up to unlock more daily tasks and larger file sizes.

Is my file secure?+

All files are encrypted during transfer and automatically deleted 1 hour after processing. PDFKit never accesses your document content.

Does this work on mobile?+

Yes. PDFKit is fully optimised for iOS and Android browsers. No app download required.

🔒 HTTPS encrypted🕐 Files deleted in 60 minutes🚫 Never read by humans✅ Free, no signup required