Security & Data Architecture
VAT Guard is a browser-based, local-first compliance application so customers can avoid desktop-software installation while reducing exposure of vendor and invoice content to the subscription platform.
Vendor, invoice and evidence data are encrypted in the customer’s browser.
The encrypted vault object is uploaded as ciphertext to a private customer-scoped cloud path for recovery.
Account, subscription, plan entitlement, terms acceptance and aggregate usage counts are stored separately. These systems do not need readable vendor/invoice content to administer the subscription.
Encryption and keys
The current implementation uses modern browser cryptography to encrypt the operational vault. Production parameters, recovery workflows and key handling must be security-reviewed before paid launch. SITUS should not hold the customer’s vault passphrase or recovery key in readable form.
Recovery
A new browser/device can retrieve the latest encrypted backup after account authentication. The customer then unlocks that backup with its vault passphrase or recovery key. Losing both can make the backup unrecoverable by design.
Plan-limit metadata
The subscription control plane may receive counts such as number of vendors and invoices in the current billing month to enforce the purchased plan. It does not need the identity of those vendors or the content of the invoices.
Operational controls before paid launch
- Content Security Policy and secure headers.
- Email verification, MFA option and session controls.
- Rate limiting/bot protection for public checkout endpoints.
- Private storage policies scoped to the authenticated customer.
- Automated encrypted backup versioning and restore tests.
- Dependency and vulnerability scanning.
- Error monitoring that avoids capturing readable Customer Content.
- Incident response and customer notification procedures.
- Independent security review before enterprise marketing.
This page is a design/security disclosure, not a certification, penetration-test report or warranty that the Service cannot be compromised.