1. Executive Summary & Zero-Knowledge Guarantee
PageScan was engineered from the ground up on the principle of Zero-Knowledge Architecture. Unlike traditional cloud scanner services that upload sensitive personal documents, contracts, bank receipts, and government IDs to remote servers, PageScan performs 100% of document processing, image enhancement, computer vision perspective correction, and optical character recognition (OCR) locally on your device.
- Zero Server Uploads: Scanned images, camera frames, and extracted text never leave your device.
- Hardware-Accelerated Encryption: All stored documents are encrypted with AES-256-GCM using the standard Web Crypto API.
- Zero Trackers: No advertising trackers, no telemetry SDKs, no behavioral cookies, and no profiling.
- User Autonomy: Export, transfer, or permanently shred your data with two-pass cryptographic erasure at any time.
2. Document Storage & Cryptographic Protection
Local IndexedDB Sandbox
Your scanned files and folders are persisted in your device's private browser IndexedDB sandbox (PageScanDB).
The sandbox is isolated according to strict Same-Origin Policy (SOP) standards and cannot be accessed by external websites or untrusted apps.
AES-256-GCM Hardware Vault
When Vault Encryption is active:
- Key Derivation: Keys are derived using PBKDF2 with HMAC-SHA-256 and 100,000 iterations, salted with cryptographic random bytes via
crypto.getRandomValues(). - Cipher: Document images, notes, and OCR transcripts are encrypted using authenticated 256-bit AES-GCM.
- Integrity Verification: Built-in 128-bit authentication tags immediately detect any tampering.
3. Camera & Hardware Permissions
PageScan requests camera access solely to display the document viewfinder for corner detection and live frame capture.
- No video frames or camera streams are recorded, uploaded, or transmitted externally.
- Hardware camera tracks are immediately stopped (
track.stop()) as soon as the viewfinder is dismissed or a scan is captured.
4. Third-Party Libraries & Sub-Processors
All processing is handled by audited open-source client libraries executing in memory:
| Library | Functionality | Data Transmitted Off-Device? | Runtime |
|---|---|---|---|
| Tesseract.js | On-device OCR text extraction | NO — 100% Local | WebAssembly Worker |
| pdf-lib & jsPDF | Vector PDF assembly & compression | NO — 100% Local | In-memory Canvas/Blob |
| Capacitor | Native Android Bridge & Filesystem | NO — 100% Local | Native Android Runtime |
5. Data Deletion & Cryptographic Shredding
When you delete a document or reset your database, PageScan applies a two-pass cryptographic shredder:
- Overwrite Pass: Memory buffers and IndexedDB records are overwritten with zero-byte blocks and cryptographic noise.
- Purge Pass: Database keys are destroyed and all object URLs are permanently revoked (
URL.revokeObjectURL).
6. Regulatory Compliance & Contact
PageScan complies with global privacy legislation including the GDPR, CCPA, and HIPAA security standards. Because PageScan does not collect or process personal data on external servers, your data sovereignty remains fully under your personal control.
For questions or verification, inspect our open-source implementation at github.com/pankaj-sudhakar/PageScan.
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