Digital Sign PDF - X.509 Certificates Free
Digitally sign PDFs with X.509 certificates (PFX, P12, PEM) for legal validity. Visible signatures and timestamps - free, private.
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About This Tool
Digital Sign PDF signs your document with an X.509 digital certificate (PFX, P12, or PEM) for cryptographically valid, legally recognized signatures. Add a visible signature with reason and timestamp for full professional effect.
Beyond a drawn signature, a digital signature proves identity and document integrity - tamper-proof in a way a scribble cannot be.
Everything runs locally in your browser, keeping certificates and documents private and usage free.
How to Use
Upload your PDF
Drag and drop the PDF you want to sign digitally.
Provide your certificate
Upload a PFX, P12, or PEM certificate with its password.
Place the signature
Add a visible signature and choose a signing reason.
Sign and download
Sign the document digitally and download it.
Use Cases
Legal Contracts
Sign agreements with a legally valid digital signature.
Business Approvals
Digitally approve documents with a verifiable identity.
Document Integrity
Prove a document has not been altered after signing.
Frequently Asked Questions
What certificate formats are supported?
PFX (.pfx), PKCS#12 (.p12), and PEM (.pem) certificates are supported.
Is a digital signature legally valid?
Yes - X.509 signatures with a valid certificate are legally recognized in most jurisdictions.
Can I add a visible signature?
Yes - add custom text, an image, a signature reason, and timestamp.