Why We Built DocTransfer
Sharing sensitive documents like pitch decks, financial reports, or legal contracts shouldn't require paying $250+/month for platforms that store your unencrypted files on their servers.
We built DocTransfer (and open-sourced it on GitHub) as a privacy-first, client-side encrypted document sharing and Virtual Data Room (VDR) platform.
Zero-Knowledge Cryptography Architecture
Most document-sharing services encrypt files at rest on their cloud storage. That means their backend servers - and anyone with access to them - can view your raw documents.
In DocTransfer, encryption happens entirely on the client before the payload leaves your browser:
- Client-Side OpenPGP & AES-256-GCM: Files are encrypted in the browser using the WebCrypto API and OpenPGP.js.
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Zero-Knowledge Key Handling: Encryption keys are kept in URL hash fragments (
#key=...), which are never sent to our servers. - Dynamic Forensic Watermarking: Recipient email overlays are rendered dynamically on the canvas layer, preventing unauthorized screenshots and distribution.
Tech Stack & Key Features
- Frontend: React 19, TypeScript, Vite, Framer Motion
- Database & Auth: Supabase (PostgreSQL with strict Row-Level Security, Edge Functions, Storage)
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Document Processing:
pdf-lib,react-pdf,pdfjs-dist - Security & Signatures: OpenPGP.js, SimpleWebAuthn (Biometric sign-in), Digital Certificate generation
- Analytics: Real-time page-by-page engagement heatmaps & viewer telemetry
Try It & Contribute
- Live App: doctransfer.app
- GitHub Repository: github.com/simplegithubs/DocTransfer3949
We would love to get your feedback on the client-side encryption flow, PDF rendering optimizations, and general user experience!
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