Understanding Signed QR Codes for E-Invoice Verification: A Complete Guide

Overview of Signed QR Code and Its Usage

The Invoice Registration Portal (IRP) generates a Signed QR Code that includes the unique Invoice Reference Number (IRN) and various critical parameters related to the invoice, along with a digital signature.

Components of the QR Code

The QR code incorporates the following parameters:

• GSTIN of Supplier
• GSTIN of Recipient
• Invoice number as assigned by the Supplier
• Date the invoice was generated
• Invoice value (including taxable value and total tax)
• Number of line items included
• HSN Code of the main item (the line item with the highest taxable value)
• Unique Invoice Reference Number (IRN)

Usage and Display of the Signed QR Code

• Format and Printing: The Signed QR Code, in Base64 encoding, can be applied by taxpayers to generate a QR code to be included on the invoice copy. The recommended printed size of the Signed QR Code is 2 x 2 inches; however, it should be adjusted to fit on the invoice while ensuring it remains readable by mobile scanners.
• Verification Process: This Signed QR Code can be validated using the offline application available on the IRP portal. The QR code is structured in JWT format, consisting of three sections—signature parameters, data, and signature—separated by dots.

Decoding and Signature Verification

Upon decoding, the parameters of the Signed QR Code reveal detailed information. To validate the signature, users can utilize the associated Digital Signature Certificate provided on the portal. Verification can be done using the Public Key available as indicated in the documentation.