Verify Signed PDF Document
Inspect cryptographic PKCS#7 & CMS digital signatures, verify signer identities, check timestamps, and detect whether document content was altered after signing.
Detected Signatures & Certificates
How Digital PDF Signature Verification Works
Inspect cryptographic signatures, certificate chains, and integrity in 3 simple steps.
Upload Signed Document
Upload any agreement, legal deed, invoice, or court filing with electronic or digital signatures.
Cryptographic Inspection
The engine parses ByteRange tables, PKCS#7 certificates, signing authorities, timestamps, and modification history.
Audit Certificate & Verdict
Receive instant forensic verdict and download an official verification audit certificate with SHA-256 integrity hash.
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Frequently Asked Questions
What is the difference between an electronic signature and a digital signature?
An electronic signature is any symbol, cursive drawing, or graphic applied to a document signifying assent. A cryptographic digital signature embeds mathematical public-key cryptography (X.509 PKCS#7/CMS) with a ByteRange digest that makes tampering mathematically detectable.
How does the system detect if a document was modified after signing?
When a PDF is signed, a /ByteRange array locks specific byte segments of the document. If any revision, page deletion, or textual change is appended to the file later, the byte offsets mismatch the actual file length, indicating post-signing alteration.
Can this verify signatures created in Adobe Acrobat or DocuSign?
Yes. All standard PDF signatures created in compliance with ISO 32000 (Adobe.PPKLite, adbe.pkcs7.detached, and ETSI CAdES) are fully inspected and recognized.
Are my confidential documents private during verification?
Completely private. Files are processed with SSL encryption, analyzed in isolated memory, and automatically deleted within 2 hours. We never read, store, or share document contents.