Signing a PDF, in plain steps
Signing a PDF with a Digital Signature Certificate takes just a few minutes once your token is set up:
- Plug in your USB token and make sure its driver is installed.
- Open the PDF in a reader that supports digital signatures, such as Adobe Acrobat Reader.
- Choose the option to digitally sign, and draw a box where the signature should appear.
- Pick your certificate from the list and enter your token PIN.
- Save the file — the signature is now embedded in the PDF.
What a signed PDF proves
A properly signed PDF shows the reader who signed it, that the signer's certificate was valid, and that the document has not been altered since. Anyone who opens it can see the signature panel and check those details.
"Signature not verified" — don't panic
A yellow "validity unknown" or "not verified" mark usually does **not** mean the signature is fake. It most often means the reader does not yet trust the issuing authority on that computer. Trusting the Indian CCA root certificate chain, or updating the PDF reader's trusted-certificate list, normally clears it.
"Document has been modified"
If the reader warns that the document changed after signing, that is working as intended — any edit after signing breaks the signature. You would need a freshly signed copy.
Bulk and automated signing
If you need to sign many PDFs at once — invoices, statements, certificates — a document-signer setup can stamp them automatically rather than one at a time. We cover that separately.
Tips
- Update your PDF reader to the latest version.
- Keep the signing utility running while you sign.
- Never share your token PIN.