Check the received document
See if the signature remains intact and whether the PDF records any changes after signing.
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Verify digital signatures and export authentication reports. Upload one file up to 256 MB. No registration required.
Technical content edited by Tools.4PDF.Net • Updated September 8, 2026Choose one file · up to 256 MB
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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
Checking the PDF digital signature indicates whether the document is signed, whether the content has changed after signing, and which certificate was used. The report can record the signer according to the certificate field, the time recorded, the algorithm, and the integrity status. The result depends on the data in the PDF, the available trust chain, the accessibility of revocation information, and how the verifier interprets each signature.
A valid technical status does not mean the identity has been verified beyond the certificate, the authorized signer, or legally effective documents. An untrusted warning may be due to a missing intermediate or trusted root certificate and does not necessarily prove the document is counterfeit. Keep the original, compare fingerprints and sender information when necessary, and use an evaluation process appropriate to the intended use.
See if the signature remains intact and whether the PDF records any changes after signing.
Check the subject, issuing organization, validity period, and the technical data of the signature.
Record the verification status for the responsible team to use in the next review step.
Practical tips
Each job uses a separate anonymous session. Learn how we handle data in our Privacy and Security.
Frequently asked questions
No. A valid status generally indicates that the signature matches the document and the certificate chain meets technical requirements at the time of verification. This status does not, by itself, confirm authority, consent, signing purpose, or transaction requirements. The authentication report is not a legal conclusion or advice.
Integrity indicates that the signed content has not been altered. Trustworthiness, however, depends on the certificate chain. The checker may be missing a trusted root, intermediate certificates, or revocation data. The certificate may also be self-signed. Review the chain details and compare them with the certificate sources that your organization accepts.
Not direct. The report states that the signature was created using the key corresponding to the certificate and displays the identification fields in the certificate. The report does not observe the person operating the device, password sharing, or the authorization process. To assess the actual identity, additional evidence and control procedures outside the PDF are needed.
Access expires after one hour and cleanup runs every five minutes. Download any results you need before they expire.