Frequently asked questions
How to verify and validate a digital signature.
How do I verify a digital signature on a PDF?
Open the document in a reader that supports digital signatures and click the signature. The reader shows who signed, when, and whether the file was changed after signing. A valid signature confirms both the signer's identity and that the content is intact.
Why does a digital signature show as not verified or unknown?
This usually means the reader does not yet trust the certificate's issuing authority, not that the signature is fake. Adding the Certifying Authority's root certificate, or enabling the India trust list, makes it validate correctly.
How can I validate a digital signature online?
Besides a PDF reader's built-in check, there are online validators where you upload the signed file and the tool reports the signer, the certificate chain, the timestamp, and whether the document was tampered with after signing.
What makes a digital signature valid?
Three things: the certificate was issued by a trusted, CCA-licensed Certifying Authority; it was valid, not expired or revoked, at the time of signing; and the document has not been altered since. If all three hold, the signature validates.
Can a digital signature be forged?
A properly issued, token-stored DSC is extremely hard to forge because the private key never leaves the hardware and any change to the document breaks the signature. The real-world risk is sharing the token or its password, not cryptographic forgery.