CRYPTOGRAPHIC PRIVACY · WORKSPACE ISOLATION · AUDITABILITY
Bank-Grade AES-256-GCM Encryption & Multi-Tenant Workspace Security
KharchaTracker protects personal expenses, account balances, and business khata records using authenticated client-side AES-256-GCM encryption, strict per-workspace Firestore security rules, JWT-verified vault key distribution, role-based access control (Admin, Editor, Viewer), and immutable field-level audit logs.
01. Client-Side AES-256-GCM Authenticated Encryption
Sensitive ledger fields—amounts, party names, descriptions, account balances, and notes—are encrypted in the browser via the native Web Crypto API (`AES-GCM` with 256-bit keys and unique initialization vectors) before cloud persistence.
- Authenticated encryption detects any ciphertext tampering automatically.
- Workspace vault keys are strictly gated behind verified Firebase Auth ID tokens and workspace membership checks.
- Optional 12-word recovery phrase backup ensures you never lose access to your encrypted vault.
02. Row-Level Workspace Isolation & Role-Based Access Control
Every Personal and Business workspace enforces server-side Firestore security rules validating exact membership UID/email and role permissions on every read, create, update, and delete.
- Admin: Full workspace settings, member management, backups, and ledger control.
- Editor: Create and update daily entries, bills, and khata records without deleting the workspace.
- Viewer: Read-only visibility for partners, family members, or external auditors.
KharchaTracker Security & Governance Controls
| Security Layer | Implementation Standard | Protection Delivered |
|---|---|---|
| Payload Encryption | Web Crypto AES-256-GCM (96-bit IV) | Confidentiality & integrity of ledger records at rest |
| Transport Security | TLS 1.3 + HSTS Preload + Strict CSP | Prevents MITM interception and XSS script injection |
| Access Control | Firebase Auth JWT + Firestore Rules RBAC | Strict row-level tenant isolation across workspaces |
| Operational Accountability | Immutable Audit Log Tab (Before/After Diffs) | Tracks who created, edited, or deleted any financial entry |
Frequently Asked Questions
Can other workspace users see my personal workspace?
No. Every workspace has its own isolated membership list and dedicated cryptographic vault key. Only explicitly invited members of a specific workspace can access it.
Does encryption slow down adding daily expenses or invoices?
No. KharchaTracker updates your UI optimistically in under 20ms while hardware-accelerated Web Crypto AES-256-GCM encryption and Firestore sync execute asynchronously in the background.