Sign the complete PDF
Attach a digital signature to a contract, minutes, or report that has been reviewed and completed.
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Sign PDF with a PKCS#12 or PFX certificate. Process up to 2 files totaling no more than 256 MB. No registration required.
Technical content edited by Tools.4PDF.Net • Updated September 8, 2026Up to 2 files · up to 256 MB
Files are protected and deleted automaticallyGuide
Three steps from the source document to the result you need.
Select the right task for your document.
Drop files or select them directly from your device.
Track progress and download your file when it is ready.
No account, no installation and no unnecessary steps.
Only this session can access your files.
Input files and results expire after one hour.
Learn about this tool
Sign PDF with P12 or PFX using the certificate file and private key to create a cryptographic signature on the document. You select the key file, enter the corresponding protective password, and choose the display location if needed. The signature allows the verifier to detect changes after signing and view the certificate information. The level of trust still depends on the certificate chain, reader configuration, and the recipient's verification process.
Please read the final version carefully before signing as subsequent edits may cause the signature to be reported as altered or invalid. The P12/PFX file and password are sensitive information that need to be protected. Only use certificates under your control. The tool generates a technical signature but does not confirm identity beyond the information in the certificate, prove the signer's authority, or conclude the legal validity of the document.
Attach a digital signature to a contract, minutes, or report that has been reviewed and completed.
Help the recipient verify whether the PDF content has been altered after the signing time.
Create a signature field on the page so the reader can recognize it and access detailed technical verification.
Practical tips
Each job uses a separate anonymous session. Learn how we handle data in our Privacy and Security.
Frequently asked questions
Not in the sense of a cryptographic digital signature. The signature image only serves a display function and does not provide a private key, certificate, or the ability to detect changes. This digital signing function requires a valid P12/PFX file along with the corresponding password. You can add a display portion, but it does not replace the cryptographic signature.
The reader can verify the signature but may not trust the issuing organization of the certificate, or may not have established a chain leading to a trusted root. The cause may also be missing intermediate certificates, revocation data, or timestamps. The recipient needs to check certificate details according to their procedure instead of relying solely on the checkmark.
No. The signature indicates that the document was signed with the private key corresponding to the certificate and helps detect changes. It does not by itself confirm the role, authorization, or intent of the signer. These factors depend on identification procedures, certificate management, agreements, and applicable requirements. Use appropriate professional guidance if needed.
Access expires after one hour and cleanup runs every five minutes. Download any results you need before they expire.