Digital Signatures & Verification (S8)

§8 — Digital signature & verification URL

Every invoice type — Normal, Advance, Copy, Training, Proforma — is signed on the SE and produces a unique verification URL encoded into the receipt QR code. The URL payload is assembled to the FRCS specification and comprises:

• Format version;
• Secure Element UID and requesting-signer identifiers;
• Invoice and total counters;
• Total amount and timestamp;
• Encrypted internal data;
• The SE signature; and
• An integrity digest (MD5) over the payload.

The signature allows any party to verify the invoice's integrity and authenticity via the verification URL / FRCS portal. The exact byte layout and QR encoding conform to the FRCS E-SDC specification and are validated by the SDC Analyzer.