Add legally binding digital signatures to PDFs to ensure document authenticity and integrity.
Upload PDF File
PDF (Supported formats: .pdf)
Max 2.5 MB
If your type isn't listed, convert to JKS using keytool
Enter password if applicable
Upload files and configure options, then click start processing
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Worried about electronic documents being tampered with or unable to prove the signer's identity? PDF certificate signing uses cryptographic technology to add a legally binding electronic signature to your PDF files using your PFX/P12 digital certificate. A digital signature is an electronic seal based on asymmetric encryption. It uses a hash algorithm and private key encryption to generate a unique signature value embedded in the PDF, ensuring the document has not been modified since signing and clearly verifying the signer's identity.
Q: Can the content of a PDF be modified after it is signed?
No. Any modification will invalidate the signature, and PDF readers will display a "document has been altered" warning.
Q: What is the difference between a digital signature and a standard electronic signature?
Digital signatures use PKI encryption technology to provide legally recognized non-repudiation and integrity verification, whereas a standard electronic signature might just be an image or text overlay.
Please ensure your certificate is valid and the password is correct. Always back up your original files before signing. For highly sensitive documents, we recommend using local offline tools. The legal validity of the signature depends on the certificate type and local regulations.
We recommend using a qualified digital certificate issued by an authoritative CA to enhance legal validity. For bulk signing needs, consider integrating standard PDF signature libraries such as iText or PDFBox. Typical example: After a "sales_contract.pdf" is signed using a company certificate, it will display a "Signature Valid" status in Adobe Reader, showing the signing time, certificate issuer, and hash validation information.
