← Blog

Income Tax PDF Digital Signature Verification — The Complete Guide

The Income Tax Department of India digitally signs a wide range of PDF documents issued through the e-filing portal and other official systems. From ITR acknowledgements to Annual Information Statements, each of these documents carries a cryptographic seal that guarantees authenticity. This guide covers every major Income Tax PDF type, explains why they all show "Signature Validity Unknown," and shows you how to verify all of them instantly using VerifySign.in.

Income Tax PDFs That Carry Digital Signatures

The following document types are issued with CBDT digital signatures:

Document	Purpose	Signed By
ITR Acknowledgement (ITR-V)	Proof of filed return	CBDT / Income Tax Dept
Form 26AS	Tax credit statement	CBDT / Income Tax Dept
Annual Information Statement (AIS)	Comprehensive income/transaction summary	CBDT / Income Tax Dept
Tax Notices (Section 143, 148, etc.)	Official communication from IT Dept	CBDT / Income Tax Dept
Intimation under Section 143(1)	Processing summary after return assessment	CBDT / Income Tax Dept
Refund Intimation	Tax refund notification	CBDT / Income Tax Dept

Why All Income Tax PDFs Show 'Validity Unknown'

Every one of these documents is signed using certificates issued by the Central Board of Direct Taxes (CBDT), which operates under India's national PKI framework overseen by the Controller of Certifying Authorities (CCA). While this is a legally recognised and technically robust framework, the CCA root certificate is not pre-loaded in global certificate trust stores — such as Adobe's AATL (Adobe Approved Trust List) or Microsoft's root programme.

This means that when you open any of these PDFs in Acrobat, Preview, or a browser, the viewer has no way to independently confirm the CBDT certificate's legitimacy — so it flags the signature status as "Unknown" or "Not Verified." The document itself is valid. The viewer simply isn't equipped to vouch for it without additional configuration.

CBDT as the Certifying Authority

The CBDT is the apex body governing direct taxes in India. It issues digital certificates for signing all Income Tax Department documents through a dedicated PKI infrastructure. These certificates are legally valid under the IT Act, 2000. The chain of trust goes: CCA India (Root) → CBDT Sub-CA → Document Signing Certificate. VerifySign.in maintains this exact certificate chain and uses it to verify your documents cryptographically.

How to Verify Any Income Tax PDF with VerifySign.in

The process is identical for all document types:

1. Download your document from the Income Tax e-filing portal (incometax.gov.in) or TRACES.
2. Visit verifysign.in — no account required.
3. Upload the PDF. VerifySign.in automatically identifies the document type and the CBDT signing certificate.
4. The verification result shows the signer identity, signing timestamp, and whether the document is intact.
5. Download the verified PDF with LTV data embedded — it will display a green tick on any device.

Whether you need to verify an ITR for a loan application, a Form 26AS for your CA, or a tax notice for legal proceedings, VerifySign.in handles all Income Tax Department PDFs in the same simple workflow. No software, no configuration, no technical knowledge required.