Privacy Policy for Due Book

1. Introduction & Overview

Welcome to DueBook, a digital ledger and bookkeeping application developed and operated by TSR Mobile Solution ("we", "us", "our"). DueBook is designed primarily for Indian shop owners, merchants, traders, and small businesses to record and manage day-to-day customer and supplier dues, transactions, payment reminders, cash calculator tallies, and business reports.

We respect your privacy and are committed to protecting the information you entrust to us. This Privacy Policy explains what data we collect, how it is stored and processed, where it is kept, and your rights regarding your information under applicable Indian laws, including the Digital Personal Data Protection Act (DPDPA), 2023 and the Information Technology Act, 2000.

2. App Classification & Non-Lending Declaration

DueBook is strictly a Personal and Business Accounting, Bookkeeping & Record-Keeping Utility.

• No Banking or NBFC Affiliation: DueBook is NOT a bank, Non-Banking Financial Company (NBFC), money lender, credit bureau, or lending institution under the Reserve Bank of India (RBI) regulations or any other statutory jurisdiction.
• Zero Loan / Credit Services: DueBook does NOT provide, offer, facilitate, broker, disburse, underwrite, or service personal loans, business credit, payday loans, cash advances, micro-finance credit lines, peer-to-peer (P2P) lending, or debt recovery/collection services.
• No Interest, Fees, or Credit Scoring: The application does not calculate interest charges, credit scores, repayment fees, loan terms, or APR.
• User-Controlled Data Entry: DueBook functions solely as a digital khata/register where shop owners and individuals manually record completed credit/debit transactions and set personal reminders for internal accounting.

3. App Architecture & Offline-First Design

DueBook operates on an offline-first architecture:

• Local Storage: All core business ledger records, customer/supplier names, transaction amounts, cash tallies, notes, and receipt photo attachments are stored locally on your device in a secure SQLite database (managed via Android Room). The app functions completely without an internet connection for all day-to-day ledger operations.
• Internet Connectivity: Internet access is required only for:
  1. Authenticating your identity via Google Sign-In.
  2. Cloud Firestore device registration and single-device security gate.
  3. Business profile cloud synchronization.
  4. User-initiated, client-side encrypted Google Drive backups and restores.
  5. Firebase Remote Config for app versioning and service notices.

4. Information We Collect and How We Use It

A. User & Account Information (Cloud Firestore)

When you sign in using Google Sign-In (via Google Credential Manager and Firebase Authentication), we collect and store the following account metadata in Google Cloud Firestore (users/{uid}):

• Email address, Display name, and Profile photo URL (from Google account)
• Active device ID (hardware ANDROID_ID) & Active organization ID pointer
• Account creation and last login timestamps

💡 Note: DueBook never collects or stores your Google account password. Authentication is handled entirely and securely by Google OAuth.

B. Device Information & Single-Device Gate

To enforce our single-device security gate and prevent unauthorized concurrent logins, we collect device hardware metadata stored in Cloud Firestore (users/{uid}/devices/{androidId}):

• Device model & manufacturer (e.g. "Samsung Galaxy M34")
• Hardware ANDROID_ID (Settings.Secure.ANDROID_ID)
• Android OS SDK version, App version name & code
• Registration and last active timestamps

C. Business Profile Data & Merchant UPI ID (Cloud Synchronization)

To enable cross-device restore of your business setup, non-financial identity fields are stored in Cloud Firestore (organizations/{organizationId}):

• Business / Shop name, Owner name, Contact phone number, Shop address, Category
• Default currency and language preferences
• Encrypted Merchant UPI ID (VPA): For your security, sensitive merchant UPI payment handles synced to Cloud Firestore are encrypted on-device before transmission using AES-256-GCM derived from the authenticated owner UID (ENC:v1:...). No plain-text UPI handles are stored in the cloud database.
• Backup settings metadata (last backup timestamp, backup file name, contact/transaction count summary)

D. On-Device Ledger Data & Zero Financial Telemetry Guarantee

The following accounting information is stored strictly on your local device:

• Customer and supplier names, phone numbers, and notes
• Debit and credit transaction figures, dates, and payment reminder schedules
• Bill and receipt photos: Saved exclusively in private internal app storage (Context.filesDir/attachments/), completely sandboxed and inaccessible to external apps, gallery scanners, or third-party file managers
• Cash calculator tallies and denomination breakdown snapshots

5. Google Drive Backup & Restore (Optional Feature)

• Isolated App Scope: DueBook requests only the restricted Google Drive scope https://www.googleapis.com/auth/drive.appdata. This scope is restricted strictly to a private, hidden application data folder (appDataFolder). DueBook cannot view, search, read, modify, or delete any personal documents, spreadsheets, photos, or files in your personal Google Drive.
• Zero Human Review: Backup payloads stored on Google Drive are never accessed, inspected, or viewed by DueBook developers, employees, or automated server bots.
• Client-Side AES-256-GCM Encryption: Backup archives containing your ledger records are encrypted directly on your device using AES-256-GCM (with 128-bit AEAD authentication tags) before upload. The encryption key is derived on-device using PBKDF2WithHmacSHA256 (65,536 iterations and a cryptographically secure 16-byte random salt). The encryption key is never transmitted to or stored on our servers.
• Payload Integrity: Backups are split into domain chunks carrying individual SHA-256 manifest checksums to prevent malformed or tampered payload injection.
• Google API Policy Compliance: DueBook's use and transfer to any other app of information received from Google APIs will adhere to the Google API Services User Data Policy, including the Limited Use requirements.

6. Android Permissions Requested

DueBook requests only the minimal Android permissions necessary for declared features:

7. Data Sharing, Advertising & Third-Party Services

• No Data Sale or Commercial Brokers: We do NOT sell, rent, monetize, or trade your personal information, ledger records, or business details to advertisers, data brokers, or any third party.
• Zero Advertising SDKs: DueBook does not embed third-party advertising SDKs, behavioural trackers, or marketing analytics networks.
• Zero Financial Telemetry: Third-party infrastructure tools never receive, log, or store your customer ledger figures, transaction entries, or debts.
• Infrastructure Processors: We use Google Firebase (Auth, Firestore, Remote Config), Google Drive (optional user-initiated encrypted backup), and Cloudflare (website CDN).

8. Data Retention & Account Deletion

Local Data Deletion: You can erase all local ledger records instantly via Settings → Reset / Delete Local Data inside the app, or by uninstalling the app.

Cloud Account Deletion: You may request complete deletion of your account and all associated cloud records at any time.

• How to Request: Submit a deletion request via our contact form at https://duebook.tsrms.in/contact?topic=delete-account or email duebook@tsrms.in directly with the subject "Account Deletion Request - Due Book".
• Deletion Action: Upon verification of your request, all associated cloud records are permanently and irreversibly deleted, including your Firebase Authentication identity, Cloud Firestore user profile, device registry, organization profile, backup settings metadata, and any associated backup tracking records. This process is completed within 30 calendar days of request verification.

9. Security Measures & Data Breach Notification

We implement industry-standard technical and operational security safeguards:

• Authentication & Identity: Standard OAuth 2.0 via Google Credential Manager & Firebase Authentication; zero account passwords stored.
• Single-Device Security Gate: Real-time hardware ANDROID_ID registration in Cloud Firestore to enforce single-device active licensing and prevent concurrent unauthorized logins.
• Client-Side Backup Encryption: AES-256-GCM client-side encryption with PBKDF2WithHmacSHA256 key derivation (65,536 iterations, 16-byte random salt, 128-bit AEAD tags) for all Google Drive backups.
• Merchant UPI ID Cipher Layer: Merchant UPI IDs synced to Cloud Firestore are encrypted on-device with AES-256-GCM derived from the authenticated owner UID before network transmission.
• Private Sandboxed Storage: Receipt photos and SQLite Room databases are stored in private sandboxed internal directories (Context.filesDir/attachments/) inaccessible to external gallery scanners, file managers, or third-party apps.
• Encrypted Transmission: All network communications use TLS 1.3 / HTTPS encryption.
• Biometric App Lock: Optional on-device biometric (fingerprint/face) or device PIN lock via Android BiometricPrompt (Class 3) to prevent unauthorized physical access in shared retail shop environments.
• Data Breach Notification: In the event of a personal data breach affecting your information, we will notify affected users without undue delay and report to the Data Protection Board of India within the timeframe required under applicable law, including the Digital Personal Data Protection Act, 2023.

Disclaimer: While we take reasonable and robust measures designed to protect your data, no electronic storage system or internet transmission can be guaranteed to be 100% impenetrable.

10. Children's Privacy

Due Book is intended strictly for adults and business users. Under India's Digital Personal Data Protection Act (DPDPA), 2023, a child is defined as a person under the age of 18. We do not knowingly collect or process personal data from individuals under the age of 18 without verifiable parental or guardian consent. If you are under 18, please do not use this application without your parent or guardian's knowledge and consent. If we become aware that a child has provided personal data without appropriate consent, we will take immediate steps to delete such information.

11. Regulatory Compliance & Grievance Redressal (India)

In accordance with the Information Technology (Intermediary Guidelines and Digital Media Ethics Code) Rules, 2021 and the Digital Personal Data Protection Act, 2023: