SdI, short for Systema di Interscambio (Sistema di Interscambio), is Italy’s electronic exchange hub for transmitting e-invoices between businesses and the tax authority workflow. It receives invoice XML files, performs basic checks, routes documents to the recipient, and returns delivery or rejection messages. In practice, SdI is the control point that turns an invoice from a local file into an auditable government record.
In cyber security, SdI matters because invoice integrity, identity, and availability directly affect compliance. If an attacker, insider, or misconfigured tool alters invoice metadata, sends malformed files, or abuses portal access, the result can be rejected invoices, incorrect stamp-duty handling, or reconciliation errors across accounting systems. Defenders reduce this risk with strong authentication, role-based access, logging, secure API or portal handling, and validation of XML content before submission. In short, SdI is both a business gateway and a security boundary.